A web GUI for Firestore that lets me work on documents like, idk, any other DBMS GUI would: the ability to select multiple records, and operate on them.
That's literally it. I don't need AI, I don't need dark mode, I don't even need MongoDB compatibility. I just want to select multiple documents with my mouse and do things to them.
Come up with your data model, explain it to the AI, and tell it to give you a CRUD for it.
I'm pretty sure it's perfectly doable to ask it to give you a dynamic crud based on the "shape" of the data in Firestore.
Sadly it's an internal tool for work, so I can't share.
Despite all the recent enshitification, I can't think of any alternative solution that would come even close to what Firebase has to offer. Authentication API is especially hard to beat (cheap and very easy to integrate).
Looking at that, I'm not sure corporate would be down for something like that as a solution for "select multiple documents in a database GUI and operate upon them". Could be wrong though.