For my S23 Ultra, after updating to One UI 6.0 because of the annoying reminder icon, problems start to appear:

• Unable to enable/disable VoLTE when using 4G connection. Forced to turn on VoLTE when using 4G.
• Battery life drains faster. With VoLTE turned on consistently, my phone's battery life is now dropping at 1% every 5 minutes or so, and I'm not even watching videos or playing games, just surfing internet pages and reading emails.
• Device Care -> Memory: RAM memory usage increased, available RAM memory dropped from 6GB to as low as 4GB when streaming videos online or playing "Boggle". Had to repeatedly Optimise, very troublesome and annoying.
• Phone seems slower and slightly laggy.
• When an app is prompted to install its latest update, the Cancel & Update buttons are positioned too close together, causing me to accidentally cancel the installation of the update on several occasions.

Anyone facing any other problems after updating to One UI on their S23 Ultra?