ok, macos it is.
here's the thing - i don't know a shit about macos. but, i can give you a link to srb2kart's .dmg file.
it's unsigned, so you probably need to bypass apple's protections, but, if you use macos, you probably already know how.
also, on windows and linux i recommend using the OpenGL mode as the game uses software renderer by default for god knows what reason.
not sure how are things on mac, but on both windows and linux you can trigger the OpenGL mode by adding the -opengl parameter. that's how the included activators/batch scripts work.
after downloading and setting up the game, connect to kart.szprink.xyz in game to race your fellow gaslighters.
have fun!!!