i use more than 3 years but i not found any password form 2 days ago

password available on my mobile but deleted from my desktop

Fixing the lost password issue

 #   Open the Firefox web browser.

1. Load about:support.
2. Click on the "open folder" link near the top of the page that opens; this opens the profile folder.
3. Close Firefox.
4. Check if you see a file called logins.json.corrupt.
5. If you do, rename the file to logins.json to fix it.
6. Start Firefox. The passwords should be available again.

https://www.ghacks.net/2019/06/14/if-you-lost-all-passwords-in-firefox-read-this/