I'm trying to help a friend with the IT around the Swiss tax declaration and now need your help, dear fellow tooteronies...

Login (#AGOV) needs MFA - either an app or a #FIDO2 key. The app doesn't run on #GrapheneOS ("your phone is rooted"), so my friend has to use FIDO2.

1) Does FIDO2 work on Windows 8.1?

2) Can FIDO2 be used with the phone to log in? Can the login be done on the PC & the authentication/2nd factor on the phone? She wants to use the PC for her tax declaration, not the phone.