I can relate to the frustration of facing similar issues. I had been working on a project for three months without any major problems. However, everything turned into a nightmare right after downloading version 29.00 
. I went through all kinds of grieving scenarios 
and wasted three weeks trying to fix these issues.
Make sure you don’t have Epic launcher or uefn Running, double check on task manager, you need to remove Referenced Folder of Fab, by going to your File Explore remove it and Restart your computer. If you do it while Uefn running or epic launcher is open the revision control will bring it back or will not let it remove completely.
Other issues that I encountered after managing to have all of assets back to Revision control.
if you migrated folders from an old project to a new one This led to conflicts in revision control between the folders of the two projects. By keeping only one project and removing the migrated folders, I was able to resolve that issue, and things seemed to be running normally again. Duplicating Projects can lead to having issues in revision control from my experience.