Oh, and Fidor Bank just answered my support request, apologized for not supporting my phone and changed the account from pushTAN via app back to mTAN via SMS, even though this isn't officially available anymore. So while this isn't the best of all possible solutions and will only be supported, as they say, for a limited time, for the time being I can now do everything with the Pro1! And the Moto Z3 Play can finally go back into the drawer, as soon as my employer's fine tech support people will have bound my Pro1 to that VPN token account... 🙂