@ohmycommodore From what I've tried out, systems where the resolution is the same as ES (probably 320x240) are fine, it's only when the resolution needs to switch that the problem occurs. You can definitely try it out and just send that command to clear out the frame buffer if you get stuck at any point. The one or two N64 games I tried worked really well, as well as psx games with enhanced resolution and the older systems with one or two frames of runahead.
I'd be interested in seeing how RT works with Pi4 and Lakka though. I haven't used it much as I have all my PSX games in chd and didn't really want to change them all over.