retropie supports neither mugen nor the switch, so...

still dabbling with it not having much luck at the moment the bor portion of paintown runns pretty well but so far any attempts to utilize the mugen portion of paintown results in codedumps the main menu is pretty much all i have running in mugen right now and it also lags

Wine only emulates the operating system, the PC Diablo binaries are still x86 so will never run on a Pi. If you want to play Diablo, there is a PSX port. Yes, N64 emulation is crap for many games, the Pi is weak and emulation is not that good anyway. A few games work well such as F-Zero X. There are apparently some improvements to N64 emulators coming so maybe the situation will get better in the next few months or year.