I have used Thunderbird for years, I think I may be forced to change! I have lost IMAP login Gmail, from Thunderbird, since the last update download (last email on Thunderbird is 6th or 7th June 2022 Thunderbird constantly says it cannot log in to GMail IMAP, requests to try again or get new password (for which it requires the password it will not recognise) Still using Gmail on my phone, have had to launch Chrome to use Gmail on my (old) iMac [running 10.13.6, High Sierra - can't update further], so I know the password is still valid. It is Thunderbird which seems to be the problem, here. Have read through various Problems/questions similar, but have not found a solution that helps

I had a similar problem with an update of Firefox, in that I was unable to use the browser - in the end I had to delete the browser, and several weeks later, re-downloaded. (This meant that I lost all my bookmarks etc, and had to re-establish passwords, but I'm now back to Firefox)