The app worked fine for its intended purpose BUT
They should really just allow people to use whatever 2FA app/s they want… Thankfully I found a desktop app (on GitHub some years ago now) that was able to give me the TOTP seed/secret (I think it displayed a QR code and the plaintext) - meaning I can use the 2FA app/s of my choice to get the codes. I just use Bitwarden for all my 2FA codes these days and FreeOTP for Bitwarden itself. It’s handy to use Bitwarden for 2FA as the codes are copied to the clipboard after it inserts the login info. If I delete this app or lose my phone or something I won’t lose access to my myGov account because I have the seed/secret in Bitwarden. I found that not all 2FA apps support the more advanced SHA512 algorithm though - which is what the myGov one uses.