I agree that auth is still a damn pain in the ass.
My last two experiences have been with Firebase and Django, both with React front-ends.
I think the state of JWT auth in Django with Rest Framework is dire. I've used the most popular packages (dj-rest-auth, which uses simple-jwt for JWT under the hood) and I've had to tweak way more than I would like to make it all work. I've been shocked to learn that this is not a solved problem in one of the world's most popular web frameworks, and I'd definitely consider using external auth in future projects.
The Firebase experience on the other hand has been outstanding. The front-end SDK is great and so is the documentation. I had to implement SAML SSO for a massive corporate customer using Microsoft AD and was able pull it off in an afternoon without a hitch. The ability to add custom claims and the like is also great - the whole thing feels really feature-complete. But then there's the fact that I don't trust Google with my user data and that I fear that at any time they could start charging onerous amounts for the service, or worse.
In both cases, the most painful bit however has been by far implementing the React front-end. Wiring the views, Redux async actions, etc. That's the part I wish I could get rid of. I see you provide some sort of front-end, but if you provided some sort of adjacent, standalone React library offering views and auth state management out of the box you'd surely get my attention - I'd possibly consider contributing code to it, too.
Overall I think the whole idea sounds great and you may be on to something: in summary, I feel that Google can't be trusted, Auth0 looks eye-watering expensive, Keycloak looks a bit complicated for certain projects, and popular web frameworks like Django may not be as good at token auth as we would take for granted.
I must be honest in that I wouldn't put your tech into production right now because I'm never a tech early-adopter, but I'll keep an eye on it, I'll seriously consider it for personal projects, and if it gets decent momentum in a few months I'll definitely consider extending it to client projects.
Congratulations for launching - I really, really wish you the best of luck.