Simulators are one of the earliest PC game genres, and remain compelling experiences to this day, even if they're not as popular as they used to be.
I like all kinds of combat flight sims; the MS Combat Flight Simulator from 1998 was something special, and I've had some similar fun in IL-2 Sturmovik. The newest civil air sims are pretty great too, I'll pop on a podcast and make a flight. They're particularly cool in VR.
I've also found the MechWarrior games to be fun, but I've only played 2 and 5. I got to play a bit of Steel Battalion with the full crazy controller at a con a few years back, and that's got to be a lot of fun once you really know what you're doing.
So what's your favorite sim?
DCS (Digital Combat Simulator)
Tons of well-simulated combat aircraft. IL-2 is probably the closest simulator to it.
DCS is what I play most of the time - particularly the Viper. I help run the unit I play with as well.
Elite Dangerous is the only other sim I play.
Look into falcon BMS
Falcon BMS is pretty nice. It's like 5$ and the latest version just got out.