@Mahekaw Try clearing both the Data and Cache of the Camera App. If to no avail you could try seeing if the Camera works in Safe Mode , if successful may be a particular app that is the issue. However if not you may wish to clear the cache partition. In Android 11 need to connect Device to computer or use USB-C Headphones.
Some more advice in this thread: https://www.slashdigit.com/fix-galaxy-note-20-camera-not-working-issue/
yes this device continuously showing this error I don't know the reason about it but still I have one way to guide you for further details see .