Compression Attached Memory Module (CAMM) tries to be a middle-term solution for that, by reducing how crappy your average RAM socket is to latency and signal integrity issues. But, at this point, I can see CAMM delivered memory being reduced to a sort of slower, "CXL.mem" device.

Only if you were pushing data through so fast that the bits got corrupted before. That's literally why AMD told Framework they won't support any other configuration than soldered RAM, in this case.

Yes. (That isn't actually possible because the pinouts are different but soldered RAM is faster.)

You might be able to dial in a higher memory overclock.