Interesting! My product is very frontend-heavy actually when it comes to the customizations (except the SSO and ok... yes the database) Could you elaborate a bit more? I am struggling to understand.
Checkout something like FaunaDB where multi-tenancy is a first-class citizen and is very much designed for social frontends that run on disperse company networks with tricky auth/role escalation. In fact, if a backend is really not needed much at ALL it is the perfect DB as it can work without one. But I'm bias since I want to work with it more.