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.
As stated previously, the sockets reduce signal integrity, which doesn't necessarily make them "bad," but is why Framework wasn't able to used socketed ram to maximize the potential of this CPU.
Basically, they need to use LPDDR5X memory, which isn't available in socketed form, because of signal integrity reasons.
Which means you won't see an improvement if you solder your ram directly, I think mostly because your home soldering job will suffer signal integrity issues, but also because your RAM isn't LPCAMM and isn't spread across a 256 bit bus.
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.