Changing to the sync on luma may get rid of the shimmering so that’s something.
Honestly though, early 3D games never looked the best. You could try an emulator on a PC which can make them look a lot better but of course then you open up a whole new kettle of fish with regards accuracy, glitches, etc.
Oh and no, Framemeister won’t be significantly different here.
Edit 2 – I’m not sure that dithering you’re seeing should be there in Resi 2, please try your sync on luma cable and report back.