I recently faced two major issues after the recent android 10 and one UI 2.0 for my note 9. First one being black crush issue with display and second one s pen not connecting. For the black crash issue I never got any solution from Samsung side since it's not a widely reported issue. Second one being the s pen connection issues. The only option I was given by the service center associate was to change the s pen. To my surprise I ended up with no expense fix. I was going through my note 9 box and found additional tips, I changed the tip of my s pen and the s pen worked like a charm.
Hope you try simple fixes before just handing over your device to hardware change immediately after service center's advice. Kindly do some research on your own to understand what the issue really is.
