I had a Galaxy S8 until a bit over a year ago and moving the Authenticator app was a concern of mine. But I had a smooth transition with the Transfer Account option in it www.theverge.com/21410260/goo...

How to transfer your Google Authenticator 2FA to a new phone

Transferring Google Authenticator to a new phone can be easy — if you’ve prepared ahead of time.

I use Microsoft's (what got me to download it in the first place was an inability to use my MS password on my 360 any longer) but I imagine there's something similar there