If you no longer have access to the authenticator app and don't have the backup codes, the usual 2FA recovery options are limited. Having access to the email and Google account helps prove ownership, but it may not bypass the 2FA requirement.
I'd first check if the old authenticator account can be restored from a backup (some authenticator apps support cloud sync). Also check if you are still logged in to Opera on any other device, since you may be able to access account settings from there and update your security options.
If neither option works, your best bet is to contact Opera support through the official channels and explain the situation. Avoid posting your email or account details publicly on the forum. Only provide account information through a verified support request.