> if you already accept "superposition" at the level of quantum states, you don't have to invoke anything new to deal with so-called "collapse"

All three interpretations of QM 'accept' superposition, construed as a mathematical construct. What's at issue is how this mathematical construct maps onto reality.

If you mean something more by 'accepting superposition', you have to spell out what that is. And doing that just leads you right back to the three different interpretations.