Add the ability to forget password or log in with just username as I forgot my newly made trial email and now is facing several motnhs of paying for a service I cnanot use!
How exactly does your problem look?
As far as I know you use Stadia together with your Google account. So if you have forgotten the password of your Google account, you need to do the Account Recovery, which you can start on g.co/recover.
This would be the only way to obtain a new passwort to your account, as this process confirms your identity.
Here you can find some more information: