If you can't login to the google account connected to the phone, that phone is bricked.
You can reset the phone by doing a force shut down, booting into the recovery menu then resetting from there. But trying to set the phone up will require you to login with the previous google account.
If you cannot access the previous google account, you cannot use the phone.
Technically you can pay sketchy services to try and crack it but I don't suggest doing that
