My experience with macOS Big Sur
Indeed a great operating system but it has its own set of flaws. the most important one is the issue with QuickTime player. If you are recording screen for longer period of duration, then the files recorded may get corrupted because of possible memory constraints.
One thing that I liked about QuickTime Player is that it auto saves the recording file but when it gets corrupted, it won’t play significant part of the video which is a shame.