What the hell year is this? Paypal is still doing user-agent sniffing to decide if you're allowed to add a passkey to your account? (confirmed by setting a Windows/Chrome agent on my Linux/Firefox browser... works just fine)
www.paypal.com/us/cshelp/ar...
PayPal Passkeys enable secure login via biometrics or device password, unique to the user and resistant to phishing. Supported on Apple and Google devices.