I'm here today to ask whom it may concern to read through this class' description. I would ask your answers to address this class in terms of balancing, its features fitting with image of a medieval knight(of course in a fantasy setting) and on your overall feeling. I am also posting two subclasses, to flesh out the possible character for PCs more. What I would like to hear mostly about are those three things:

• Is this class outperforming another available classes, or is it underperforming? What are its weakest and strengths?
• Can this class offer versatility in creating PCs, or is it a bottleneck for creating a goody two-shoes?
• What would anchor valid additional subclass' options, or improve those present already?

The idea behind the class was to make a specialist whose training and education made his/hers horizons broader, and skiss more refined. Abilities were meant to cover a fair bit of possibilities, but enforce thinking what features would be best to use, not spamming everything you have in two turns in combat.

If someone wants to read an introduction to the class like in official sources, it can be found here at dandwiki.

And while comments are insightful, I would prefer answers.

Class Features
As a Sir Knight you gain the following class features.

Hit Points Hit Dice: 1d10 per Sir Knight level Hit Points at 1st
Level: 10 + Constitution modifier

Hit Points at Higher Levels: 1d10
(or 6) + Constitution modifier per Sir Knight level after 1st

Proficiencies Armor: All armors, shields

Weapons: Simple weapons,
martial weapons Tools: Calligrapher's supplies, vehicles (land)

Saving Throws: Strength, Dexterity

Skills: choose three from Athletics, Stealth, History, Religion, Animal handling, Persuasion, Intimidation

Equipment You start with the following equipment, in addition to the
equipment granted by your background:

• (a) chain mail or (b) scale mail or (c) leather armor (a)

• a martial weapon and a shield or (b) two martial weapons

• (a) ranged martial weapon and 20 arrows or (b) ranged martial weapon and 20 bolts (a)

• Diplomat's Pack or (b) Explorer's Pack or (c) Scholar's Pack

Table: The Sir Knight

Level	Proficiency Bonus	Features
1st	+2	Fighting style
2nd	+2	Weapon Mastery, As Good as My Word
3rd	+2	Way of Life
4th	+2	Ability Score Improvement
5th	+3	Extra attack
6th	+3	Way of Life feature
7th	+3	Weapon Mastery improvement
8th	+3	Ability Score Improvement
9th	+4	Way of Life feature
10th	+4	Ability Score Improvement
11th	+4	Extra attack(2)
12th	+4	Ability Score Improvement
13th	+5	Way of Life feature
14th	+5	Weight control,Weapon Mastery improvement
15th	+5	Paragon of Verity
16th	+5	Ability Score Improvement
17th	+6	Golden soul
18th	+6	Perfect warrior
19th	+6	Ability Score Improvement
20th	+6	Way of Life feature

Fighting style

You adopt a particular style of fighting as your specialty. Choose one of the following options. You can't take the
same Fighting Style option more than once, even if you get to choose
again.

Archery You gain a +2 bonus to attack rolls you make with ranged weapons.

Blind Fighting You have blindsight with a range of 10 feet. Within that range, you can effectively see anything that isn't behind total
cover, even if you're blinded or in darkness. Moreover, you can see an
invisible creature within that range, unless the creature successfully
hides from you.

Defense While you are wearing armor, you gain a +1 bonus to AC.

Dueling When you are wielding a melee weapon in one hand and no other weapons, you gain a +2 bonus to damage rolls with that weapon.

Great Weapon Fighting When you roll a 1 or 2 on a damage die for an attack you make with a melee weapon that you are wielding with two
hands, you can reroll the die and must use the new roll, even if the
new roll is a 1 or a 2. The weapon must have the two-handed or
versatile property for you to gain this benefit.

Interception When a creature you can see hits a target, other than you, within 5 feet of you with an attack, you can use your reaction to
reduce the damage the target takes by 1d10 + your proficiency bonus
(to a minimum of 0 damage). You must be wielding a shield or a simple
or martial weapon to use this reaction.

Protection When a creature you can see attacks a target other than you that is within 5 feet of you, you can use your reaction to impose
disadvantage on the attack roll. You must be wielding a shield.

Superior Technique You learn one maneuver of your choice from among those available to the Battle Master archetype. If a maneuver
you use requires your target to make a saving throw to resist the
maneuver's effects, the saving throw DC equals 8 + your proficiency
bonus + your Strength or Dexterity modifier (your choice).

You gain one superiority die, which is a d6 (this die is added to any
superiority dice you have from another source). This die is used to
fuel your maneuvers. A superiority die is expended when you use it.
You regain your expended superiority dice when you finish a short or
long rest.

Thrown Weapon Fighting You can draw a weapon that has the thrown property as part of the attack you make with the weapon. In addition, when you hit with a ranged attack using a thrown weapon, you gain a +2 bonus to the damage roll.

Two-Weapon Fighting When you engage in two-weapon fighting, you can add your ability modifier to the damage of the second attack.

Unarmed Fighting Your unarmed strikes can deal bludgeoning damage equal to 1d6 + your Strength modifier on a hit. If you aren't wielding
any weapons or a shield when you make the attack roll, the d6 becomes
a d8.
At the start of each of your turns, you can deal 1d4 bludgeoning
damage to one creature grappled by you.

Horseback Flyby Charger Your mount can take a Dash or Disengage as a bonus action, provided you made an attack against a creature after moving at least 20ft, and hit.

Weapon Mastery

Your dedication in honing your battle skills with specific weapons
gives you an edge against enemies, as well as many tricks hidden up
your sleeve. Starting from 2nd level, choose two types of weapons, or
one type of weapon and a shield, to be your mastered weapons. While you
wield only your mastered weapons you gain the following benefits.

Parry When hostile creature hits you with a melee attack, you can use your reaction to add your proficiency bonus to your AC for that
attack, potentially causing the attack to miss you.

Harmful strike As a bonus action, you can choose to deal an additional 1d6 damage to your next weapon attack. This damage die changes to 1d8 at 7th level, and to 1d12 at 14th level.
You can use either of these options a number of times equal to your
proficiency modifier, and you regain all expended uses after you
finish a long rest.

When you gain new level in this class you can change your choice of
mastered weapons, representing you shifting your training, as you
focus on a usage of different weapon types.

As Good as My Word

Cultural implications of your view as a Sir Knight is widely known. Starting from 2nd level, you have advantage on Persuasion and Intimidation skill checks when dealing with creatures coming from races or cultures which knighthood left a significant imprint upon, such as humans, bugbears, hobgoblins, and many more.

Way of Life

At 3rd level choose your Way of Life Archetype. Choose between the Inquisitor or Commander, both detailed at the end of the class description. Your choice grants you features at 3rd level, and again at 6th, 9th, 13th and 20th level.

Ability Score Improvement

When you reach 4th level, and again at 8th, 10th, 12th, 16th and 19th
level, you can increase one ability score of your choice by 2, or you
can increase two ability scores of your choice by 1. As normal, you
can't increase an ability score above 20 using this feature.

Extra attack

Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.

The number of attacks increases to three when you reach 11th level in
this class.

Weapon Mastery improvement

As you gain more and more experience in battle your deadly arsenal
widens. Starting from 7th level, while you wield only your mastered
weapons you gain the following benefits.

Clinch control If you successfully parry an attack you can choose to grapple your enemy. As a bonus action on your turn you can attempt to shove a creature grappled by you in this way. Alternatively, you can use your bonus action to lock your weapon with weapon of creature you are grappling, making it impossible to use both weapons until the grapple ends.

Peripheral vision As a reaction, you can give yourself advantage on Dexterity saving throws against effects that you can see, such as
traps and spells. To gain this benefit, you can't be blinded,
deafened, or incapacitated. You can also choose to use your reaction to
ignore half cover and three-quarters cover on your attack, potentially
causing this attack to hit.

You can use either of these options a number of times equal to your proficiency modifier, and you regain all expended uses after you finish a long rest.

Weight control

Starting from 14th level you can wield versatile weapons with one arm
and benefit from it like wielding it with two hands, and when you use
a weapon with heavy property, this weapon lacks this property for you.
Also your carrying capacity doubles.

Weapon Mastery improvement

You are becoming a grandmaster in battle arts. Starting from 14th level, while you wield only your mastered weapons you gain the following benefits.

Masterful Athlete As an action you can choose to sprint, which gives you extra movement for the current turn. The increase equals triple your speed, after applying any modifiers. You cannot choose to sprint if you used this action on your previous turn.

Positioning As a reaction, you can give yourself a benefit of a half-cover until the end of the current turn.

You can use either of these options a number of times equal to your
proficiency modifier, and you regain all expended uses after you
finish a long rest.

Paragon of Verity

Starting at 15th level, if you are telling the truth, any creature
that can understand you knows you are telling the truth. Additionally
you can not be forced to state a lie if you do not wish to, and any
magic or feature used against you fails and stops working the instant
it would attempt to make you lie.

Adamantine Soul

Your resolve is a tale of legends. Beginning at 17th level your alignment cannot be forcibly changed, and you become proficient in Charisma saving throws.

Perfect Warrior

There is little more a master like you can achieve on a battlefield.
Starting at 18th level, you can use your weapon mastery options
regardless of weapons or shields you wield. Additionally, you honed
your precision to unthinkable extent, allowing you to forcibly push
yourself beyond mortal level. When you roll for an attack roll,
ability check, saving throw or damage roll, you can forgo rolling and
take maximal possible result from dice instead. When you use this
feature, you gain one level of exhaustion.

And the subclasses:

Inquisitor

You choose to give your life in the name of protecting decent folk
from the machinations of magic, from horrors beyond the mortal sight,
from the unknown of darkness. You study magic, for you need to know
your enemy. You have eye for details, for you need to wage war where
enemy lurks exactly behind your back. But in the end your fire will
disperse the darkness.

Know your enemy

When you choose this way of life at 3rd level, you gain proficiency in
the Arcana and Insight skills if you don't already have it.

Tools for the Job

When you reach 3rd level, you gain the ability to cast a limited
number of spells. You can cast the following spells, requiring no
material components: detect evil and good, detect magic, detect poison
and disease, identify, sanctuary, protection from evil and good, find
traps and purify food and drink. Charisma is your spellcasting ability
for spells gained from this subclass, and your spell save DC = 8 +
your proficiency bonus + your Charisma modifier. You can cast each of
these spells once, and you regain ability to do so after you finish a
long rest.

You also learn Create Bonfire and Control Flames cantrips.

And the Pyres will Burn

Starting at 6th level, when you cast Create Bonfire, the spell creates
a magic bonfire that fills a 10-foot cube instead. Additionally, you
can use your bonus action on your turn to move the bonfire to another
location within range.

Nowhere to Run

Even if someone is adept at running away, you are master of chase.
Starting at 9th level, when you see a creature cast a spell or use a
feature to teleport somewhere, you can use your reaction to foil the
escape. Your target must make a Intelligence saving throw with DC
equal to your spell save DC. On a failure, the teleportation attempt
is a failure, and the spell slot, if used, is wasted.

You can use this feature a number of times equal to your Charisma
modifier (minimum of 1), and regain all expended uses after a long
rest.

Defend the Innocent

Starting at 13th level, you gain resistance to damage from spells.
Additionally, you can use your reaction to give this resistance to
another willing creature that you can see, no further than 30ft from you,
until the start of your next turn.

You can use this feature a number of times equal to your Charisma
modifier (minimum of 1), and regain all expended uses after a long
rest.

They Can See Only Fire

Your soul is a burning hell for all that sin, and eyes are the windows
of the soul. Starting at 20th level, each creature of your choice
within 30 feet of you that can see you must make a Wisdom saving throw
against your spell save DC. If the creature's alignment is evil it
makes the saving throw with disadvantage. If the creature fails, it
looks into your eyes and sees every single sin it has ever committed.
The creature is then frightened of you. While frightened in this way
creature cannot target you or include you in area of effect of any
spell or ability. Affected creatures can repeat the saving throw at
the start of their turns, provided you are not within the line of
sight. If a creature's saving throw is successful or the effect ends
for it, the creature is immune to this feature for the next 24 hours.

Commander

You chose your life is to lead others, seek glory in great battles,
raise armies and command them, lead them to victory. You are a shining
example for others, you inspire men and woman to follow your lead and
rise in the path of greatness.

Mount and Blade

Starting at 3rd level, your mastery as a rider becomes apparent. You
have advantage on saving throws made to avoid falling off your mount.
If you fall off your mount and descend no more than 10 feet, you can
land on your feet if you're not incapacitated.

Finally, mounting or dismounting a creature costs you only 5 feet of
movement, rather than half your speed.

Call to arms

You raise your voice, rallying your most trusted companions to battle.
Starting at 3rd level, you can choose a number of friendly creatures
equal to your Charisma ability modifier (minimum of one), which become
rallied for one minute. Those creatures gain temporary hit points
equal to your level in this class + your Charisma ability modifier.
While rallied, once every turn each creature can add your Charisma
modifier to one of its weapon damage rolls, provided it still has
temporary hit points. If a creature loses all those temporary hit
points, it instead can add your Charisma modifier to its saving throw
for the remaining duration.

After you use this feature you cannot do so again until you finish a
long rest.

Share ability

Starting at 6th level, you can use your reaction and expend one use of
chosen weapon mastery feature to grant chosen benefit to one friendly
creature that you can see.

Divide and Conquer

Starting at 9th level, when you reduce a creature to 0 hit points you
can make another attack as a part of the same attack action against
another enemy within your range. After that, you cannot use this
feature again until the start of your next turn.

The last Obstacle

Starting at 13th level, as an action you can designate a creature. If
the target is reduced to 0 hit points, you and each creature friendly
to you in 60 foot radius regains hit points equal to your level in
this class + your Charisma modifier.

After you use this feature you cannot do so again until you finish a
long rest.

Banner Lord

When you reach 20th level, your mere presence bolster the morale of
your allies. If you are not unconscious, you and each friendly
creature in a 120ft radius that can see you gains temporary hit points
equal to 5 + your Charisma modifier at the start of each of its turns.

Oh, and multiclass options, if they provide anything:

Prerequisites. To qualify for multiclassing into the Sir Knight class,
you must meet these prerequisites: 15 Strength or 15 Dexterity

Proficiencies. When you multiclass into the Sir Knight class, you gain
the following proficiencies: simple weapons, martial weapons, light
armor, medium armor, vehicles(land)