@GabsGM: Please restart your phone in Safe mode, as this will disable all third party apps and help to determine if the problem is stemming from an external source.
To enter Safe mode, press and hold the Power button until the 'Power off' prompt appears on the screen then release > Touch and hold Power off until the 'Safe mode' prompt appears then release > To confirm, tap Safe mode.
With Safe mode active, monitor the performance of the device for a few hours, based on the frequency that you encounter the issue. If you find that the restarts no longer occur, then please restart your Galaxy S21 as you would normally and uninstall any apps that you have added to the device since you first encountered the issue. It won't be possible to determine exactly which app is at fault, therefore we recommend approaching this via a process of elimination.
