Alright, what make you think that other people are Playing Games watching Videos all Time???
I also set my Refreshrate on 60hz, and my most usage are Whatsapp, Twitter, MembersApp, and I can't complain about my Time on Display.
Watch my Screen On Time yesterday!!! Amazing.
And I havw spend Time on Google Play, cause for an App that didn't work on downloading it.
9hrs screen on time, I watched a bunch of Articles, Tech News ectr.
There is probably a problem with your device buddy, but maybe there are some Apps running in Background of the S21Ultra???