@dankcushions well, they are OCing the pi4 to 2.16Ghz (cooling tower ? maybe water cooling ?), downclocking the emulated cpu to 30% (so any game that used more than 30% of gamecube's cpu speed is out of reach), and that's still far from perfect. The situation will probably improve when we get affordable SBCs at the level of a snapdragon 845, but we are still probably 2-3 years away from that.
The specific emulator I'm having trouble with is mupen64plus-glide64
the lr-mupen64plus works fine but looks awful and won't load high res textures. The mupen64plus-glide64 emulator worked great until I had to reinstall everything for other reasons. No system hardware has changed since I've started this.