Passwords gone, addons disabled after Windows 10 update
All of a sudden, my Firefox was completely empty. All my passwords were gone, but managed to get them back from another browser. I thought all my addons were gone as well, but it turned out they were all disabled for some reason.
My Windows version that effed things up (I don't know, but it's the only thing that changed) is 20H2 19042.1348.
Sometimes when the browser thinks there is a problem with the profile, it will create a new one.
Look on your desktop. Do you see a folder called; Old Firefox? Look inside. Look for the folder with the latest creation date.