Please consider going over to your dial pad and type in *#0*#, this will bring up a number of tests to try.
One is a series of coloured panels to switch between.
Also consider putting the phone into Safe Mode which disables downloaded apps but leaves the stock ones working and then see what happens.
If they don't help then seek support from a Samsung Experience Store or Samsung Service Centre.
Current Phone ~Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+ Samsung One Ui 3.1/ Android 11.