XSX vs PS5

[who is ted danson?]

The emulation of older games is pretty damn good on the Xbox Series X but there are still a lot of games not backwards compatible.
Including some fan favorites like Need for Speed: Most Wanted, PGR4, Forza 4, SEGA Rally, Stranglehold and a whole bunch of licensed games (LOTR, Spider-Man, 007, The Simpsons etc.).
Some got new releases like Tales of Vesperia and Bayonetta, some got remakes but a lot of stuff is unplayable on Xbox now.

If its just a few games you want like Ninja Gaiden, Mass Effect, Bioshock etc. most are on PlayStation 4/5, Switch or Steam/PC.
Plus we're seeing more and more remakes of obscure games from that era like Sonic Generations and Lolipop Chainsaw.

Jut need to wait for the emulators to catch up

Luckily there is not much "stuck" on XB1 https://en.wikipedia.org/wiki/Category:Xbox_One-only_games