problem: When I give a mca villager guard archer or adventurer a musket they don't use it as a weapon it just sits in their inventory.

solution: for the musket to count as a weapon or just a bow the mod allows pillagers and skeletons to use them without problems maybe you
could tweak around with that.

im on v 1.20.1 forge btw
link for mod
https://www.curseforge.com/minecraft/mc-mods/ewewukeks-musket-mod

was my info unclear? and if so sorry.

Nope, nothing is unclear :)