Almost 5 years I have not used GA. I use Authy for the security of my account. I don't know if GA can be duplicated to other phones, but Authy can. You only need to remember the password with your email. I don't know this is a plus or a minus. Maybe if you lose your phone it will be easier to get backups.
With the latest update on google 2fa, you can make a QR code backup of the sites you want to. All you need to do is to:
- Open the google 2fa
- Click on the three dots at the top right corner
- Click on transfer accounts you want to backup
- Click on export accounts
- Making sure all the site you make authentication for are marked
- Then click on next
You will see a QR code, you can backup the QR code which consist of all the sites you selected and can be used on any new device to retrieve your 2fa authenticator.
If you don't have the recovery code for the exchange (I assume you are trying to login to an exchange) all you can do is contact the customer service department of the site and request that they reset your code. Be prepared to go through KYC and waiting days and weeks for them to respond.
What I have noticed about exchanges is that if no kyc was done before by the user before the lost of the account, the account will be lost forever. But, if the person has verified his account before the account loss, then the customer care can request for certain credentials to help prove the user is the right owner of the account, which will be used to recover the account to the rightful owner.