the PS5 has the best exclusives for sure as well as a big back catalog of amazing PS4 games for dirt cheap. PS5 exclusive games are rarely on any significant sale though. PS5 would be good if you're pretty sure you want to play the Sony exclusives. You could such with PS4 games until PS5 games come down in price and still have several years of amazing games to play.

Xbox's big draw is game pass. You know what Xbox offers. If you're happy with the games but just want a much better experience then it's a safe choice. Especially if you like any of the backward compatible games that go on sale all the time.

Another good option would be to buy a PS4 Pro used and play a bunch of PS4 games while waiting for a good time to upgrade. As I said above, the back catalog of cheap and excellent games can keep you stayed for a very long time if you're interested. You might even consider pairing this with a Series S and get a better Xbox experience without jumping straight to a $500 console.

I think if I were to only have one console I would choose the series X because of game pass and my love of 360 era games. I have a gaming PC though, though, so my Series X feels largely irrelevant now. A PC and a PS5 will let you play the best of everything for many years to come.