If I were to get a graphics card, I'd get it ASAP. Prices can rise, and the earlier you buy, the longer the time you'll have with the card before it becomes dated. 3080 will be better than the PS5, but you wont have any exclusives. If exclusives don't matter to you, then there's no reason to consider a PS5. I've been burned out on PS exclusives for years, as they're all just single player story based corridors of fighting enemy hordes. It gets old after doing it in the uncharted games, tomb raider, batman, etc. I just don't enjoy it, or paying for PS+, I wasn't able to finish any PS4 game this gen outside of Detroit: Become Human. The other 3 games I finished this gen were either on PS3, or PC, and that's when I beat it.
But, Windows 10 comes with xbox live, and you wont have to pay a subscription to use it on PC.
However... Seeing that you have a 2070 Super... I don't see why you wouldn't want to at least wait until next year, and get a 4080. There wont be a big enough improvement to justify, unless you coming from a 1000 series or older.