Oculus Quest 1 and 2 are standalone VR headsets, which means that the single device is everything you need to play games. You don't need PC, but if you have it you can also use headset to play PCVR games through Steam – with wire or wireless if you have capable wifi.
Even though XR2 chipset in Quest 2 is weak in comparison to beefy PC with NVIDIA RTX 3090, the games are optimized for it and runs smoothly at 90/120Hz. A lot of games are made in low-poly style exactly because of poor hardware, but some games can pull off some pretty decent looking graphics (Eleven, Climb 2, Robo Recall, etc.). I expect that graphics will get much better (HL Alyx better) on standalone VR headsets with Apple's take on this segment.
Even though XR2 chipset in Quest 2 is weak in comparison to beefy PC with NVIDIA RTX 3090, the games are optimized for it and runs smoothly at 90/120Hz. A lot of games are made in low-poly style exactly because of poor hardware, but some games can pull off some pretty decent looking graphics (Eleven, Climb 2, Robo Recall, etc.). I expect that graphics will get much better (HL Alyx better) on standalone VR headsets with Apple's take on this segment.