I would like to see the villagers and illagers decorated and fashionable, but their armor trims are not displayed in the game when they are wearing armor with the required trim. I play on version 1.20.1, mod version 5.0.0. Perhaps this is due to rendering.

Forge or Fabric? What kind of method did you use to put armors on villagers and illagers, dispenser or summon with nbt?

I used the /item command to equip the armor.
It didn't work in both Forge and Fabric.

Any other mods/resourcepacks are you using? Is it working with optifine?

Copy that, I'm going to find out and fix it.

When I install Optifine on Forge even without this armor mod, it crashes. :(
Minecraft runs on TLauncher for me, I can’t find out the reason for the crash.
The client works well on Fabric.
But here is a list of mods that are installed on Fabric:
Earth2Java
Illager Invasion
Headed
PuzzlesLib
Cloth Config
Architecture
Forge Config API Port
Mod Menu