@Tsuk1 You could use this tutorial that uses GeckoLib 4:
https://www.youtube.com/watch?v=3zqxU7vjHmQ
It is designed for 1.19.4 but it works for 1.20.1, I have tested.
All you would need to do is only make it for a helmet.
I'm not sure how you would do the general item model.
There is no error in that log.
But I can see you are using optifine as well.
You can't use optifine/rubidium/embedium together.
You have to choose one major graphics overhaul mod.
If you are just dumping large numbers of random mods in your mods folder don't do that.
Add mods individually or in small groups and test them so you know which mods cause problems.