@H4RR1S I have only had minor issues with Beta and final version. However there are members like yourself with more pressing issues. You could clear the cache and Data of affected apps, though seems there are quite a lot. As mentioned good idea to clear the cache partition after an update by the following steps:
Press the Power key to restart the device.
Good practice to also use the Galaxy App Booster https://itnext.io/magic-trick-of-galaxy-app-booster-684e1984576e
If that does not help matters consider a factory reset (vital to back up Data beforehand though). However there should be a bug update for your device in due course. https://eu.community.samsung.com/t5/galaxy-s21-series/26-nov-21-bukg-latest-android-12-bugfix-update...
I do not work for Samsung or make Samsung Products but provide independent advice and valuable contributions.
My Device- S21 Ultra 5G ( SM-998B/DS ) CSC= BTU , 12GB/256GB
One Ui 4.0,Android 12 Official Version.