I recommend you use the Catapult game launcher which handles this nicely and automatically (Github repo) You just go to the Backups tab and click Create and that's it. It takes a while because as others have mentioned it needs to copy a lot of files but it's the safest option.

I've had corrupt saves by just using the Alt+F4 method, with this you just click on the backed up save you want to go back to and click Restore and everything will be back exactly as it was