Is it possible to upcast ritual spells?
For example, say I'm a level 11 bard that has the spells Leomund's Tiny Hut (LTH) or Alarm. LTH is a 3rd-level spell with the ritual tag; Alarm is a 1st-level spell with the ritual tag. Since they are rituals, they can be cast without expending a spell slot.
Is it possible to cast LTH or Alarm at, say, 6th level (Bards at 11th-level have one 6th-level spell slot) as a ritual, thus making it harder to dispel the enchantment?
The reason I ask this is that spells like LTH and Alarm are pretty good for setting up camp, but they can be dispelled by an attacking party with a simple Dispel Magic – and since they are a 3rd-level spell or lower, the spell effect is ended immediately without the enemy even needing to roll.
In my mind, if a spellcaster has the ability to cast spells at 6th level, they should be able to imbue a ritual spell they cast with that level of power, as a ritual.
Ritual spells can't be cast at higher levels unless you spend a spell slot
The rules for rituals state that:
This means that when casting as a ritual the spell must be cast at its normal level. However do note that these spells can also be cast normally (emphasis mine):
So if you really want to have a higher level tiny hut, for example, you can spend a higher lvl slot to cast it normally.