For fantasy games...
Dragonbane
Castles & Crusades
I'd like to consider some different genres as well for more of a palette cleanse.
I have Call of Cthulhu (which I would probably run with Pulp Cthulhu overlay)
Would like to find a streamlined sci-fi game to consider. (Maybe Esper Genesis? I think Starfinder is too much. I don't think Starfinder 2 will be much better for my needs. I don't know about Voidrunner's Codex - I'd like everything in one book instead of requiring purchasing A5E and other genre books.)
I've looked at Scum & Villainy - it's just too different for us.
At the risk of being overly blunt...
Looking into as many as 9 new systems doesn't sound like you're actually reducing your RPG work load. It sounds more like you're just moving it around. If the root cause of all this is that you have too much stress and are burning out, teaching and DMing new games to your players won't help in the long run, and will probably make things worse in the short run as you introduce multiple new systems. You need to actually step back.
If you do want to find a new system, pick one. Just one. Anyone who wants to play with you as a GM can learn that one system. Wait at least 6 months before even considering a second system.