hello, how did you reset your windows system? in case it was through the built-in refresh option, it may be the case that they created a backup of your old data: https://www.howtogeek.com/223821/what-is-the-windows.old-folder-and-how-do-you-delete-it/

if you have a windows.old folder your old firefox profile may be in there: Profiles - Where Firefox stores your bookmarks, passwords and other user data

In the event that the passwords information is lost, you should record all information in a separate text file somewhere else on your hard drive, or written down. You can easily copy and paste if you need to do so. If you are concerned about someone else looking at that file, you can compress it using a password.

Not remembering your Firefox Account password was a fatal mistake.

If you would reset the password for your Firefox Account (Sync services) now your data would be deleted from the Sync server. The original password was the decryption "key" for your data; a different "key" wouldn't work.