re: Just bought a gaming PC what are some good PC games?

Sign up for Steam and GOG if you haven't already. Start adding stuff to your wishlist. Sign up for isthereanydeal.com , and it'll alert you when stuff on your wishlist goes on sale. Sales under 60% aren't usually worth it, but I'm a patient dude.

I'm heavily single player, and I don't know your preference, but this is what I have installed from Steam (not Epic, GOG, etc.) right now:
Baldurs Gate 3
Expeditions Rome
Fallout 76 (meh, since you're just coming back, Fallout New Vegas and Fallout 4 are better places to probably start, and a cheap way to try out a franchise)
Hearts of Iron IV
The Outer Worlds
Pirates!
This War of Mine
Warhammer 40k: Chaos Gate, Gladius and Rogue Trader
Wartales

Just make sure you actually read the recent reviews for games, and don't just go by the overall thumbs up/down for games.

I also suggest buying the cheapest Yakuza in the series, and seeing if you like it. Definitely want an XBox One controller for stuff like that, not keyboard and mouse.