I know you are looking for people that actually did it themselves. However, tried this ?
Export tokens already created in the authenticator
For some unfathomable reason, of all the authenticator apps we checked out, only Google Authenticator provides an option to export tokens that are already created in the app and import them on another device.
Perhaps the developers of the other apps think their cloud-sync feature does the job just as well. That’s partly true. But the cloud is of no help to those who already use Google Authenticator and are looking to try an alternative by quickly transferring existing tokens to a new app. Alas, developers of the alternative authenticator apps don’t make life easier for such defectors.
In any case, exporting tokens in Google Authenticator is very straightforward: Click on the three dots at the top of the screen, select Export accounts, and mark the accounts you need. After that, a huge QR code containing all of the selected tokens appears on the screen. All that remains is to take a screenshot and save the image securely in your password manager.