how to use disguise in API

It is the same as adding models to a normal entity. If you want to view your model, add this:

if(modeledEntity.getBase().getData() instanceof BukkitEntityData data)
    data.getTracked().addForcedPairing(player);

If it's modified like that, is there a way to hide the player's base model when changing the player model? I know just using hidePlayer doesn't work.

When you remove a model applied to a player as described in the wiki, only the connection between the model and the player is severed, but the model itself does not disappear.

When can I expect a response?