Yeah, IIRC the force between nucleons is actually mediated by virtual pions, which are themselves composite particles. (Which is why it doesn’t get stronger with distance, like happens with the direct strong force)

It turns out that glueballs don’t come from “taking the quarks out” of regular matter but by some kind of direct excitation of the colour charge field – a thing I didn’t even know was a thing.

Yep. It’s like if photons (which are the fundamental particles of electromagnetism) had a magnetic or electric charge.