> Document store -> FerretDB

Love FerretDB, but it doesn't really replace MongoDB's GridFS which is main reason why most people who are really using Mongo now day. Anyone knows a good replacement for GridFS?

Why would anyone use GridFS for any serious use case? It costs 10-20x as much as storing the files on S3. If unless you already have all your data in MongoDB and don't want an additional dependency for a small number of files it makes sense, but it definitely is not a case for using MongoDB by itself.