I want to use Maneuvering Attack to move my mount, and then make an attack action on the creature I move towards. However I want the weapon attack that triggers this combat manoeuvre to be made as a ranged weapon attack against the same opponent, and explicitly with my bonus action prior to the mounts movement. If you need a reason – it's a cool visual for me.
I'm assuming no multi-attack/extra attack or action surge. Just using a straight-forward bonus action and action combination.
When you hit a creature with a weapon attack, you can […] choose a friendly creature who can see or hear you. That creature can use its reaction to move up to half its speed […]
I would use Quick Toss:
As a bonus action, you can expend one superiority die and make a ranged attack with a weapon that has the thrown property. You can draw the weapon as part of making this attack. If you hit, add the superiority die to the weapon’s damage roll.
but I am limited to one manoeuvre per attack:
You can use only one maneuver per attack.
Similarly Crossbow Expert is no use, as that bonus action attack is after using the attack action:
When you use the Attack action and attack with a one-handed weapon, you can use a bonus action to attack with a hand crossbow you are holding.
If there's multiple ways, I'll pick the lowest level, then fewest character choices (e.g. fewest multiclassing choices, feat choices, spell choices…)
Best Answer
Swift Quiver
The only way I know of to make a ranged weapon attack with you bonus action without it being tied to the Attack action is swift quiver:
The downside is that it's a 5th level ranger spell, requiring 17 levels in that class (or 10 in the bard class for magical secrets). It's also self only (or as written can only target/benefit your own quiver), so you can't get your friends to help you.
Haste
Perhaps a better option would be haste. It doesn't actually use your bonus action, but an additional action so you still have your bonus action available afterwards. It's only a 3rd level spell, on multiple class lists and is castable on others so could be cast by one of your allies instead of you.