Would it be possible to add a way to disable certain slots for certain players, as in hide them in the inventory and prevent rendering/ticking/etc.? I'm mainly thinking about this for the purpose of Origins compatibility, as in trinket slots that are only available to specific origins.

Doable with generic EAMs in 3.0.0

The rendering and ticking part isn't really necessary for what I'm trying to do, as I can handle that part on my end. It would just be preferable to be able to hide the slots in the inventory.

Trinkets 3.0.0 will have a more malleable slot system for stuff like this. Unfortunately, it is out of scope to bring back to 1.16, so it's going to be necessary to wait until 1.17 proper

Ok.