Cool idea. I've been trying to hack an internal dashboard for my team, is not a fancy project but is crucial for accountability. The pain is to rely on out DB or tools such as Retool to hack a simple project. I think this solves that problem. It seems to me than having a basic KV store as a service is a great thing to ease the development of simple yet important projects.
I was wondering, I hate Firebase, but why was it a pain for you?