If you have a chance. Try to zoom from ultrawide to maximum zoom and back to ultrawide while you are recording video on S21 Ultra. And you will see, it look so jerky on 30fps and worst on 60fps cz it's skipping between the lens. I tried it when I was on Samsung Center nearby.
Hopefully it will be improved. Let me give you comparison with your competitor from some sources.
I find that on my Exynos S21ultra Hardcomment when shooting 4k 60fps video it zooms in fine from wide angle to 3X but at 10X it flickers everywhere as if no stabilization is occurring but when taking photos the stabilization is brilliant at 10X. I find low light video quality at any resolution is poor and noisy even compared to that shot by my old Note 9. I believe whatever problems most of us have at the moment are software related and that eventually we will ALL be seeing our cameras full potential as it really is a fantastic piece of hardware. Yes we should all be getting phones that are perfect out of the box I know especially with a £1000+ unit but I have been here before with other phones over the years. This should not be happening though for sure.