I got nostalgia going through this. Most people didn't get the idea of how revolutionary it could be if adopted well, somewhat like magic. All apps are ready to use at single click. People fail to see that because they have spent days and months on it, except founders. Love you bro...do it...
BTW, during my competitor research I found this one dude in the USA, ex-startup raised $50mil in pre-seed round under 45 days to build a new startup right after selling the last one against Oauth, oneID, one login, and many more. But he is in the b2b market. And, I learned that it's not that they cannot do it, they just can earn much and are not ready to educate for user adoption. Plus, security is a real issue, the hackers are always looking for loops. Later, Amazon too launched basic SSO, used in the Snitch website.
Your approach is a bit user-exhaustive, unlike the Google manager, always looking to store all details. After months of research, I knew even I would make it, it's unlikely anyone will use it unless I have some huge distribution network, on collaboration or personal.
Anyway make some noise and sell it to highest bidder. BTW did you check Bharatpe, ex co-founder building OTPless, I was laughing at their value prop during research. Somehow they are also b2b and still alive. They are doing well, saving few paisa per OTP for business, by using WhatsApp for free. I mean WTF. Good luck...look for different approaches and distribution media.