[Fenris447]

I'm trying to think of a decent example for you to pull from. My most extreme Configurable work was for the Artificer Infusions, but that might overwhelm you (there's so much there that it gives me a headache looking at it again).

Maybe try the Tasha's variants Configurable. Look at how it manipulates itself when you grab certain abilities, opening up different lists depending on your initial selections. You can put eval scripts into your subclasses that can target your configurable, and manipulate the fields within that configurable that govern how many selections you're allowed from each table.

If you wanna start easier, look at how the Battle Master subclass opens up a new table on the Fighter tab and grants X number of selections from that new table. You can do the same thing, just with the similar fields on a Configurable.