summery
the first person hand animations break the immersion when using the tacz gun mod also the camera rotation dosent work

Running Environment

• Minecraft Version:1.20.1
• ParCool Version: 3.2.1.2-R
• Forge Version (optional):
  +other mods and links tacz:https://www.curseforge.com/minecraft/mc-mods/timeless-and-classics-zero
  first person model https://www.curseforge.com/minecraft/mc-mods/first-person-model
  shoulder surfing https://www.curseforge.com/minecraft/mc-mods/shoulder-surfing-reloaded
  optifine hd u i6

Detail
i was trying to make a selection of mods shaders and maps to make minecraft into a first person and third person shooter and then i saw the parcool mod i downloaded it and tested it in 1.18.2 bc of a map named edge craft [basicly the mirror edge map] and it was amazing and then i tested it in 1.20.1 there no was camera rotation and the hand movement breaked the immersion with the tacz mod
also if you could tell me how you did the animations i will make some animations for using tacz with parcool

Additional Data
here some screenshots
with fov animations on

with fov animations off

Thanks for reporting.
You seemed to try already, but for now you can disable first person view animation as temporary solution

As for animation implementation of ParCool, it hooks rendering event with mixin and animator classes handles it.