I have CIT Resewn 1.17.1. Here is my screenshot of the game:

• Here is the CIT and model data:
  amethyst_piano.zip
• My path is C:\Users<user>\AppData\Roaming.minecraft\resourcepacks\StickyChannel92's Custom Textures\assets\minecraft\citresewn\cit\10-23-2021
• or C:\Users<user>\AppData\Roaming.minecraft\resourcepacks\StickyChannel92's Custom Textures\assets\minecraft\mcpatcher\cit\10-23-2021
• My mods (folders don't count):
  
• latest.log
  latestlog.txt
• Here is the texture pack I'm trying to get to work (my own pack):
  StickyChannel92's Custom Textures.zip

Any idea how to get the model to work?

I need the full log, the one you sent only has the issues with New Default+'s broken paths.

latest.log

The properties' 3rd line is

model=optifine/cit/10-23-2021/amethyst_piano

even though you renamed the optifine directory in the pack to citresewn.

You also appear to have Eating Animations installed which has bugs related to CITs not showing up. You'll have to remove it to fix the issue as well.

The properties' 3rd line is

model=optifine/cit/10-23-2021/amethyst_piano

even though you renamed the optifine directory in the pack to citresewn.

You also appear to have Eating Animations installed which has bugs related to CITs not showing up. You'll have to remove it to fix the issue as well.

OMG. Thank you for the help! This fixes my problems with CITs not loading in. Now I have to go and fix my item models. ;)