Is that all you have lost?

Firefox 80+ has a logins-backup.json file in the profile folder that can be used in case of issues with logins.json or to undo an accidental delete of a login, so you can check if you can find this file in the profile folder or in a backup and replace the current logins.json. Make sure to keep a backup copy of all involved files (logins.json and key4.db and logins-backup.json)

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

Help -> More Troubleshooting Information -> Profile Folder/Directory: Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

If you use a Primary Password then you can prevent losing passwords by canceling the PP prompt. You need to logout beforehand by canceling a PP prompt, e.g. by clicking the eye icon in Lockwise (about:logins).

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.

Thank you for your answer. Unfortunately I've already tried using another profile but without success.

I did not say to use another profile.

I did not say to use another profile.

Sorry, I don't understand. Got the logins.json and key4.db and logins-backup.json but now what do i do? Thanks again for your help.

See instructions here: https://support.mozilla.org/en-US/questions/1348997#answer-1439410

Sorry but i don't understand the next steps. I found the profile folder and I found the files, now what do i do? How can I recover my lost password from this files? Sorry bu I don't understand the steps of your first post. Thank you.

sorry my friend I think if you do not have any backup of your email and password but for next time made a note file and save your emails and other details in that note file.

sorry my friend I think if you do not have any backup of your email and password but for next time made a note file and save your emails and other details in that note file.

That's my fear :( . I relied too much on Firefox. I made backup of all my data, now.

What is it you do not understand?

Do you see these Google domains in either logins.json or logins-backup.json if you open this file in a file viewer or text editor or in Firefox and do a search  ?

Yes, I see. I opened them with text editor but the password are encrypted

Yes, the passwords are encrypted in logins.json and logins-backup.json, but you see the hostnames as plain text and thus can search the files for google.com as this domain is usually involved if you login to a Google service. They may of course also show in usernames that use a GMail address, so do not get confused.