0. I use traveler's backpack for fabric 1.21 (everything even cloth config and cardinal are the latest version)

1. Unable to craft the netherite enhancement for backpack, doesn't show up in crafting table with unknown recipes on, and doesn't craft when craft manually too.

Or do I have to update cloth config and/or cardinal comp ?

You mean netherite backpack or netherite tier upgrade?

I can't craft both, or is it uncraftable, like the bat backpack ?

do you play on server

I play offline, solo world

can you craft other backpacks and things?

Yes I can craft every craftable items and backpack from the mod, it's just the netherite backpack and upgrade that I can't craft, I play full survival, no commands.
The only other mods I have doesn't affect the storage (mods to cut trees faster, and mod to see health bar).
I added the mod after beating the dragon too.

what recipe you use for backpack and upgrade

these

That's not how you craft it


These are the correct recipes