ok, macos it is.
if you want to, you can try building srb2kart-saturn yourself using srb2bld. according to the table in it's readme it should work fine on macos.
oh, and i almost forgot:
saturn uses opengl mode by default, while vanilla kart uses software mode, which sucks.
i don't know how stuff works on mac, but on windows and linux you would add -opengl as a launch argument.
if you are more knowledgable on how macos works and you can recommend better ways to srb2kart, let me know!