Update: I found a workaround to not use Windows Hello.
On my Android phone, I opened Chrome & logged in to my account. I immediately discover a horrible security risk: Chrome asked me which account I wanted to login to, and I selected one of the ones already logged into GMail on the phone.
The risk? Google suggests that I can login using a Passkey on the phone using fingerprint, facial identification, or using the phone's screen lock code!
This allows anyone with access to the phone to also have full access to the Google accounts on the phone. No more requirement for the 2FA yubi keys like before!
If someone had access to my lock screen code in the past, they could only access my email logged into GMail. No access to any of the settings of the Google account itself.
It's now a lot riskier than in the past, as it provides full access to the account! No need for your yubi keys anymore.
Continuing with this horror show of security:
I plug my new yubi key to my PC and make sure to name the key with a unique name & disable FIDO2. Save the settings on the key. This disables Passkeys, as I don't want to save any identity data on the key itself and only want to use it as a 2FA device.
I go back to Chrome on Android, go to my account settings and then security settings. I click to add a Passkey then "Save Another Way" -> "Another Device"
Note: if you make the mistake here of choosing one of your Google accounts, it'll save the Passkey to your Google Password Manager & sync it! If you're paranoid like me & want to keep things offline, click very carefully on "Another device"
Plug the yubi key then touch it. It's now enrolled as a 2FA device without saving your account data on it.
What worries me is that now my phone is considered an active Passkey and I need to poke around to remove it later.
Final thoughts: I think this overall implementation puts users at a higher risk than to actually improve security and privacy.
Google is giving excessive access to our accounts using less security controls...
I was able to remove my older yubi key from my account using the Chrome on Android session. It didn't ask me for any 2FA key or code or any validation.
Someone could enroll their own keys with access to your face, fingerprint or lock screen code.