I post this as an answer, because someone might be as stupid as I am :]
I browsed various old backups and found the settings.php line that grants admin permissions to anonymous user, and it worked.
If you add:
$config['user.role.anonymous']['is_admin'] = 'true';
in your settings.php, every anonymous user is admin. That way I could get back into admin panel and uninstall TFA and Google Authenticator. Deleted the line, logged back in as user1 and installed both modules again.
Handy way to do it, if you don’t have drush. But not recommended for production sites obviously.