My bookmarks have gone following an update. Sync is On , but it makes no difference

Every time I go into firefox there seems to be another update to download. I conform to ensure I'm up to date. The latest has changed my display to a basic display. All my bookmarks are gone. I cannot access the back up file on my W11 computer. I have a new android phone and I installed firefox on that, but I have yet to use the application as a browser, on that phone. I tried to recover from the phone, but it does not give me the options to select to follow the steps firefox says I should take. It does not allow me to scan the QR code. I desperately need my bookmarks. If I go to the help, obviously others have the same problem. I see the questions but no answers, I am signed in. I have been trying now for 2 hours. Please help. Jill

Why does Firefox do this? Its not the first time this has happened to me, but now I'm lost.