You're not missing anything by not having this on Mac. I've been playing San Andreas on Xbox Series X, since it's free on Game Pass, and... oh my. It's terrible. It defaults to a very shaky 'fidelity' graphics mode, which can't keep up a 30fps refresh rate, and even in 'performance' mode the framerate completely tanks in busy areas. The textures have mostly been upscaled by AI, and it shows. Where a human has gone in and edited things, there are brand new spelling mistakes, and some complete abominations in the smoothed-out faces and twisted character models. Luckily the dark lighting means you often can't make out characters' faces at all.
It feels like some sort of fan-made project to port the game to Unreal Engine, like they ripped the files from the Steam version and threw this together while they wait for a cease and desist notice from Take 2. Except I think if actual GTA fans had been involved in the making of this, it wouldn't be such a steaming mess.
From what I've read of the other versions, they're all pretty bad, on all formats. If you want 4K at 60 fps on PC, well for some reason it seems to be more demanding than Red Dead Redemption 2. On the plus side, all the songs they cut out of the 'definitive' editions are still present in the game files on PC, so somebody will probably go and mod it back together again. But it will still be the worst version of the games by far, and Take 2 has actually removed the orginals from Steam, so they're just history now.
More vandalism than remaster, I think.