One UI 6.1 sucks

[Sshiv]

Since one UI 6.1 arrived at my S21+:

Screen flickrrrrrrrs

Apps terminate spontaneousoy

Calls drop

Etc. 

[meself]

Several models had had some issues a fix should be coming

[Belaythatorder]

You can try performing a partition cache clear which can be useful for the software bugs that sometimes come with these OS/security updates. Here are the strps:
https://www.galaxys21usermanual.com/wipe-cache-partition-samsung-galaxy-s21/