Hey mate!!
This is my first ifixit answer so please help me improve….
I think you should reset the phone. To do that
Firstly you need to backup everything (like your photos, videos, contacts and any tying of importance )
Then go settings and search for reset and select something that say “factory data reset” or “ reset data and settings”
If the problem persits I think any note 20 ultra would be in it’s warranty period so just take it to samsung service center
Do suggest ways in which I can improve…
Cheers