I typically use screen on time as a better measure. Run time does not really reflect a phones usage equally for the sakes of comparison.
As for my phone settings, I run 5G and I do have a 5G sim on a 5G network so no compromises.
My screenshot shows you 5h SoT, NO charging, over a days use and still 50% left. My settings remain, 5G, WQHD+ 120hz. The battery life is the best Samsung have produced by far on a flagship, I have no doubt.
You may not be aware of this but part of the reason is because the S21 Ultra has a new OLED emitter which is over 25% more efficient than both the S20 and Note 20 series. That combined with the newer chipset on a better node results in substantially better battery efficiency.