I think unique user ID's a re a useful tool for a variety of use cases like voting or other similar one person one vote situations. I thought I read about some company who did this for the country of Lithuania or Estonia a few years back, but I didn't save the article. I wasn't to interested in KYC at the time. But you may find that article combined with your ideas may help you make some headway in your project.
I personally thought that instead of having your ID verifications tools spread out over all the various vendors you deal with daily, who have to confirm your ID, that having a central repository verify your ID to all other vendors was a better solution. Then only one place would have to harden it's security to be unhackable. But part of me while thinking mathematically that there were less places to hack, so more secure, I wondered if the one place would be seen as a honey pot of sorts, which attracted hackers because it was a challenge.
I think we are very early in this new technology, and hopefully we will figure out some of these issues in my lifetime and improve the usefulness of this technology.
I confess to having a perhaps unhealthy passion for this field, because it earns so little compared to my two real jobs. Sometimes I think I have wasted five years learning about cryptocurrency. But a little voice keeps telling me nothing you do for your brain is ever wasted, so I indulge myself.