I think stockfish reasonably qualifies as superhuman AI but not even remotely "general". Similarly alphafold.
> Actually solving it is not a requirement for AGI.
I think I see what you're trying to get at but taken as worded that can't possibly be right. Otherwise a dumb-as-a-brick automaton that made an "attempt" to tackle whatever you put in front of it would qualify as AGI.
I would agree as long as there is a general mechanism to represent problems. It is AGI, but would perform poorly on benchmarks compared to better AGI.