I owned a series s, now I have the series x. Basically cpu is slightly slower but not much, less ram, and a little bit weaker gpu.
That said if you’ve got an older TV or monitor or just don’t have much cash get a series s. If you’ve got a 4K TV that can handle hdr and have older disc based games or have to have better graphics get the series x. Personally I’m glad I upgraded to the series x. Not that the series s was terrible but I feel like sometimes you can tell a difference. The graphics just seem a bit more crisp imo.