2nd-factor WebAuthn should work fine with Android phones today. Any Android phone with a current version of Play Services and Chrome should be able to scan the QR code, if it doesn't work then it's a bug (or, at least, an old QR scanner).
When you say "nothing happens": what's the QR scanner? Do you have Chrome installed on the device? What are the app versions (from Settings) of Play Services and Chrome?
When you say "nothing happens": what's the QR scanner? Do you have Chrome installed on the device? What are the app versions (from Settings) of Play Services and Chrome?