lawman Based on the information provided, I could list about a dozen options for you to try. However, might be less time consuming if you could describe the issue a bit clearer. Such as:
Do you have Google Play services installed in the profile you are using? This is needed for this functionality.
Are you trying to sign in to an app or through a web browser? Which app, web browser and/or website are you signing in to?
What specifically is displayed on your screen when you try to sign in with a passkey?