It’s important to note that while the Xbox Series S only outputs at 1440p resolution when you’re gaming, the console is capable of displaying streaming apps in 4K HDR. HDMI 2.0 is also fairly standard and can be used for 240Hz at 1080p, 144Hz at 1440p and 60Hz at 4K. One of the exciting new features of the Xbox Series X and Xbox Series S is the ability to run games at 120 FPS, providing a smoother experience than previous generations that capped out at 60 FPS. With a new generation of consoles comes new hardware capabilities. If your system can run 120 fps without affecting performance, then go for it. I would cap it higher than your refresh rate so even if your frames drop (for example, if you capped it at 100, and it drops to 60), you won’t experience serious differences.