@thefliik - I have thought in detail about this. As a person who has built a medium-sized project in Firestore, and working on one in DGraph, I can tell you DGraph is more production ready by far than Firestore. I would not say the same thing about MongoDB, which seems to be production ready (even though I now hate noSQL). There are many situations you simply cannot even use increment / decrements in Firestore to use counters. Try building a follower feed with Firestore and Algolia. It is impossible, because neither of them allow joins.
That being said, DGraph is not 100%, but it is 90%. The extra 10% pretty much can be done with work arounds of Custom Lambda Mutations, and Custom DQL Queries. Firestore has no work-arounds.
I would argue to just switch your entire database to DGraph.
You can search on nested relations in DGraph, you just may have to currently build your own DQL Custom Queries.
Everything can be done in DGraph, you just may have to currently do a little bit more work than WHEN DGraph GraphQL gets more features.
Why manage 3 databases (or 2), when you can manage 1.
J