It could be the Sensors are not giving the correct information to your device.
Open the Samsung Members app > Click on Support > Diagnostics > View Tests & run the Diagnostics for the Sensors.
See if you get any error messages?
Have you tried Toggling Off & On Rotation from the QS Tiles?
You could also try Booting into Recovery & Wiping Cache, and see if that fixes the issue for you?
Instructions for Both Wiping Cache & Factory Reset (if needed).
Power of your device & Wait a few seconds.
Press & HOLD the Power + Volume UP buttons, until you feel the device vibrate. Release BOTH buttons & wait a couple of seconds until you see the Recovery Menu.
Use the Volume button to Scroll down to Wipe Cache & Select with the Power button.
Wait a few seconds until the Recovery Menu Defaults to "Restart Now" & Select with the Power Button.
Your device will Reboot.
Factory Reset is the same as above, but instead of Selecting Wipe Cache, you Select Wipe Data Factory Reset.
⚠️⚠️⚠️
BEFORE you Factory Reset, BACKUP your device with Smart Switch.
When your device Boots up, it will be to the Welcome screen, same as when you first received your device as new.
⚠️You'll need to know your passwords etc, So write them down if you need to⚠️
