There's a new version of Antutu benchmark which does appear to be better optimised for the newer chipsets on the phones as well as android 11. I ran it on my Exynos S21 Ultra 512GB and scores are vastly different from the previous version, I got 755462. I've also ran it on my Exynos S20 Ultra 128GB which has also seen a huge score bump to previous versions (623,915). I'm curious if anyone who has a Snapdragon variant of the S21 (or any other Snapdragon 888 or 865 device) could post some results to see how they compare.
Whilst the scores overall are in the Oneplus 9 favour the temperature and battery have a distinct lead on the S21 Ultra (at least according to my results). I'm very impressed in how Samsung have optimised the performance on the phone to deliver such a great balance.