What are your settings? They should be: imap.gmail.com on 993 (or pop.gmail.com on 995), SSL/TLS, smtp.gmail.com on 587, STARTTLS (or 465 SSL/TLS); for both servers, OAuth2 authentication, User Name = email address.

Remove passwords from Saved Passwords in Options/Privacy & Security, allow cookies in Privacy & Security, restart TB, enter the account password in the OAuth browser window when prompted.

If that doesn't work, there's another app interfering, such as antivirus or VPN.

http://kb.mozillazine.org/Using_Gmail_with_Thunderbird_and_Mozilla_Suite

to get a new password, it requires me to give a phone so it can text me a code. oops... I only have a land line! What to do, what to do?

If you have a working password for accessing through webmail, look up the password in the browser's settings, then apply it in TB as described above. If you don't have a cell phone to receive a code, can you receive the code by email with the recovery address registered in the gmail account?