Is it possible to "authenticate with passkey or send OTP?"

[ptmkenny]

I'm using SimpleWebAuthn with a Drupal backend.

Previously, I had my users log in by entering an email address and then sent a OTP via email.

Thanks to SImpleWebAuthn, I can now use passkeys instead. Since the account name is an email address, users can log in by entering their email address and then authenticating via passkey.

However, now I have two log-in forms (OTP + passkey), both of which only require an email address. This is confusing for users, so I'd like to simplify this into a single login form:

1. Attempt to authenticate via passkey.
2. If no passkey is available on the device, send an OTP email.

However, when I call startAuthentication(), if the device does not have a passkey available, then I get a popup with a QR code, "Scan this QR code with a device running iOS 16 or later..."

Is there a way to skip this popup and send an email OTP instead (abort passkey login, and fall back to OTP)? Or is this just how the passkey flow works?