If the auto-saving works fine on a custom folder you assigned, it indicates the project auto-saving feature indeed works on your PC.

Do you use any cloud-syncing or backup service of your Windows user folders?

In my experiences, OneDrive, which is overly promoted by Microsoft and enforced with the auto-syncing after Microsoft kidnaps users to sign into Windows with a Microsoft account/email, is pretty buggy and frequently locks file and folder access.

It sometimes might cause the file writing outside the Windows File Explorer won't work at all. The file access problem might also occur with some antivirus or cloud drive software despite it does not commonly occur on all different PCs or file paths generally.

Dropbox does a better job on background file syncing without locking access, comparing to OneDrive, but I don't really use Dropbox.

Sort out the above factors if you only want the auto-saving to put files at default path on your PC.

So, I altered the destination folder for Autosave files, and it is now saving files I can find in those other locations. Then I change it back to the DEFAULT folder and guess what...wait a few hours, not a damn autosave file in sight. What a joke.

Plenty of time passed now, and besides I have been editing projects all week. Not a single autosave. Not one.