Help with custom model data armor

I want to make a resource pack where custom model data armor is a different look of armor
This is going to have a datapack eventually where you craft a diamond piece and a red dye and it gives the custom model data
It is not working currently. It is a purple and black item in my hand, and looks like diamond armor on my head. Here are the only logs:
net.minecraft.class_1092
Worker-Main-21
Missing textures in model minecraft:diamond_helmet#inventory:
    minecraft:textures/atlas/blocks.png:test:models/armor/diamond_red
12:35:08.450
net.minecraft.class_1140
Render thread
Missing sound for event: minecraft:item.goat_horn.play
12:35:08.450
net.minecraft.class_1140
Render thread
Missing sound for event: minecraft:entity.goat.screaming.horn_break
12:35:08.595
net.minecraft.class_5944
Render thread
Shader rendertype_entity_translucent_emissive could not find sampler named Sampler2 in the specified shader program.```
If you want any code, please ask.