Hey there, I experienced a similar issue, as a user of both platforms. Unfortunately and fortunately, both are good options for secure authentication, except, I had to authenticate with eye scanning, and finger print on my Tablet, as well as my iPhone. I was afraid of disabling one or the other and being locked out. I would recommend starting at the root of authentication and trace back to that pivotal moment you enhanced your security. I would suggest downloading your passwords securely, preferably, printing them. Of course as a last resort. If you can find your bug and untangle yourself without loosing access to important websites that is. It sounds tricky. I did however found refuge and trust in one platform. So once you find which biometric is causing the glitch I’d do a split path on your choice of Oauth.
Hope you get untangled and let me know if you untie your knott.