You say it doesn’t use the hardware correctly, but the reason it can’t run in the S is because it’s got less RAM than last gen hardware, and they can’t get split screen to work because it needs more RAM. As the article points out, they have Microsoft engineers coming in trying to help them get split screen running, and they still might not be able to get it working until next year. That’s not an optimization issue. They would happily just disable split screen on the S like they did on the Steam Deck, but Microsoft parity requirements mean they can’t.

I remember seeing GTA V on the Xbox 360 and marvelling at the 20 fps on the lowest possible settings.

The last Xbox I owned was the 360 (I still have in in the closet). I made a choice to go with Sony’s PlayStation and a good Linux gaming PC to cover almost all my games bases. But I do want ALL the games to come to Xbox players.