[joshxyz]

Id say try em out as you see them fit. Postgresql for relational, redis for cache or some streams, elasticsearch for search, clickhouse for analytics.. each of them is intended for different use cases.

The managed instances by cloud vendors (microsoft azure, google cloud platform, amazon web services, digitalocean) should also help you getting up and running without worrying about the infra side of things on small scale projects

Bit outdated but comparisons

https://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis