Another community member gave some good suggestions here: https://community.cisco.com/t5/duo-mobile-app/duo-mobile/m-p/5300587#M1133
There's a comprehensive list of suggestions in this Duo knowledge base article: https://help.duo.com/s/article/5640
Duo cannot access an Instagram account or so anything from our side to restore access. Only Instagram can help with that.
Whenever someone decides to protect a third-party account with Duo Mobile as a passcode provider, it's important to do these things:
1. Make sure to save whatever backup codes that other account provides during MFA/2FA setup BEFORE you log out of that service. Store the codes in a safe and secure place. Instagram example: https://help.instagram.com/1006568999411025
2. Make sure you have Duo Restore enabled in Duo Mobile, including the option to backup third=party accounts. Note the specific requirements for iCloud and Android system backup mentioned in that guide to ensure the secure data from Duo Mobile is included in your backups.
3. If you are upgrading to a new phone, it's a good idea not to get rid of your old one until you've verified that your restore of Duo Mobile completed successfully and you can use codes from your new phone to log into apps. If for some reason the codes from your new phone didn't work, you should still be able to log in using codes from your old phone in order to disable 2FA/MFA and set it up again from your new phone.
Duo, not DUO.