Quivers might be enchantable.

If the problem to become enchantable really is because they're containers.
Maybe the solution is to change them to be no containers anymore.
Just modifying to no need to put arrows inside them to ranged weapons continue working.
But still needing a quiver in a hand slot for bows and crossbows attack the targets.

Nowadays, the system of making or buying arrows is completely unnecessary in the game.
Just watch when players switch bows/crossbows to a new one and many times they just drop their arrows or bolts on the ground.

It's much simpler to allow:

~ the attacks to be automatic (when quiver + ranged weapon equipped together)
~ attacking sprites to be based on the ranged weapon (similar to wands/sceptres)
~ and let the quivers to be enchantable too.

Agreed! Just have it so you reload the quiver by right clicking it F.E.

Interesting!