Google will frequently ask you if you want to connect to a backup email account or a designated recovery phone number. Ideally, you should have a backup account and remember your login information, or continue to have the same phone number. Google will send you a Gmail password reset email or an email to specify the verification text and send the Gmail verification code to the backup account option. You can use this to access your account and reset your password.
Source: https://www.kequery.com/internet/how-do-i-reset-gmail-password/