VRR (a feature that's on Xbox Series X/S since those consoles launched) improves visual performance by mitigating visual artifacts like screen tearing. It does so by dynamically matching the refresh rate of your TV or monitor to the PS5's output. Sony says VRR can help render scenes faster and reduce input lag.
If your PS5 is connected to a HDMI 2.1 port on a compatible display, VRR will be switched on automatically for supported games. Several titles will receive VRR optimization updates, including Marvel’s Spider-Man: Miles Morales, Marvel’s Spider-Man Remastered, Astro's Playroom, Ratchet & Clank: Rift Apart, Resident Evil Village, Call of Duty: Vanguard, DIRT 5 and Destiny 2.
VRR optimization patches may be released for other games in the future. However, Sony says you'll be able to switch on VRR for any other game. This might cause some issues, depending on the specific title, your TV and the game's graphics settings. You can toggle VRR on or off through the Screen and Video section of the system settings.