I think people are talking about different games.
I was playing Fallout 3 on the Series X (it's in this video:
https://www.youtube.com/watch?v=SzeBm0XBcOk&pp=ygUSZmFsbG91dCAzIHNlcmllcyB4It really is just Fallout 3 as it was on the 360, but with the Xbox backwards compatibility team making it 60fps 4k, and the game loading in high res textures at any draw distance. Making it basically like Fallout 3 vanilla on a modern PC.
I literally popped in Fallout 3 discs I bought on a thrift market for a euro.
And I think it looks and plays really well. In 20 hours I have encountered one bug, which was a freeze.
Oh hey, the backwards compatibility team is another thing Xbox does not have anymore...
I also played Fallout 4 remastered on my PS5. Seems nice enough, but has a ton of issues. And 3 did capture my attention more. There is an official remaster of Fallout 3 coming, but honestly I assume Bethesda will do a worse job than the Xbox backwards compatibility team did, and ask money for it. They have become a failure of a studio in my opinion. Like, how can the Fallout 4 port take years after they announced it, come with the most minimal enhancements of which some don't work.