Either you haven’t actually enrolled passkeys on your account or you are just missing it somehow. I’ve not used windows but the UI is extremely obvious on macOS.
If you try to sign in with passkeys but there are none found on the local machine it will ask if you want to use a usb auth or QR code scan.
I so get the prompt to insert a USB key, but I don't know why, when it never gave me an option to create one in the first place (I set mine up in the Microsoft Authenticator app). There is no option to sign-in with a QR code.
This is why passkey are a failure, no one knows how they work, and even one someone claims they know, the reality is often different.