Xiaodi Wu has that copypasta ready to go because people encounter your problem 523 times per minute, across Earth. (That's just the related internet post count from non-AIs; actual usage is estimated to be 700 times higher.)
associatedtype is literal. It's not "associatedtypeorprotocol". That necessitates workarounds like result builders, type erasure, and implicitly opened existentials.
This is not easy for humans to deal with; it's a workable model, but not good enough.