wipe cache and data for the camera app and see if that helps.

if not then it might be a hardware issue. was the phone dropped recently?

 

I had a similar problem on a samsung a20. nothing helped, i had to reinstall android. so you will probably have to. i also had a problem with screen recording. i constantly have problems with this phone, i think to buy s21 ultra. the technologeek article helped with screen recording. i advise you to solve this problem quickly, good luck!