I actually use an older iPhone that sits in a drawer as a secondary 2FA device. Just scan the barcode on both devices and you have a good backup to help recover accounts that don't provide printable codes.
I do similarly and also print out barcodes/recovery keys and put them in a safe place in case all else fails. Echoing some wise words from this post [1], insure your backup solution can be restored. I tend to test the QR code on my primary phone, print out a few copies for safe keeping, and then read the QR code from the printout into Ng backup phone.
[1]https://news.ycombinator.com/item?id=13551905