With June security patch update, samsung bricked call functionality. Submitted logs and called USA customer care but no use. Most of the unlocked versions were effected according to posts in various forums. 

Amazon music not being displayed neither in media control nor in lock screen like 90% of the time. It's really annoying. Also while casting any video/music volume control doesn't control the casted one like it used to do but rather control the phone ...

Certain apps like iMobile are not displaying the colors properly especially on the confirmation dialogue boxes like log out.  

In beta update navigation gestures are hit and miss.Back gesture gives weird results sometimes and so the home.Minor issue 

Finally Samsung started rolling out June security patch for S21 Ultra which includes fixes for camera lag.