Appreciate the educational back-and-forth between interesting companies in here!
Having just done a review of auth vendors (including FusionAuth + Auth0), I think your product addresses a much simpler use-case. FusionAuth and Auth0 support complex multi-tenancy setups and tie that into enterprise SSO providers, and all that's configurable on a per-customer/application basis with logical separation inside the auth vendor. I don't believe you support that level of complexity yet.
The nitty-gritty of auth does suck for most projects/early startups, but once you start selling to mid-size customers (B2B) they'll demand features that require what FusionAuth/Auth0/similar competitors offer.