Probably up to now we already had the months update and Dec is behind. I came here looking for the answer why also. Was also hoping we saw the notes to see what was added and or fixed. The pixel line is getting the Dec update with over 100 items in it to help fix Android 12 issues.
I got mine yesterday (S10 +) but it was on Android 11 one UI 3.1. One UI 4.0 beta was just released this morning for S10 series and installed it.