Hi,
I haven’t really tried anything yet apart from checking the ScreenUpdateSetting.
Let me show you a video of how it runs, maybe I’m expecting too much? I feel like this morning it runs much better than last night for some reason. Walking around is actually quite fine, apart from the flickering on the ground. In interiors you can can hear the slowdown / stuttering in the sound mostly. Again, I don’t really know how it should run, so I’m fully expecting your reply to be: that’s how it is 
Video:
https://streamable.com/ffjus
Edit: One more thing, I’m trying to add a OOT launcher icon following this guide
But I’m having trouble figuring out where to link to the mupen64plus as it is not in the cores folder?