By default, the Galaxy S20's screen is set to the standard 60Hz refresh rate, which gives a familiar look and feel to the phone.
But you can set the screen to 120Hz for a faster and smoother overall experience, and it's absolutely worth it. It might reduce battery life a little bit, but I have no complaints so far on the Galaxy S20 Ultra. Battery life is still among the best I've ever experienced on a smartphone.
To change the screen from 60Hz to 120Hz, head to Settings > Display > Motion smoothness > tap High refresh rate (120 Hz) > then tap Apply.
Also note that the 120Hz option is only available for the FHD 1080p resolution.