MongoDB is complex, that’s true. But DynamoDB or GCP Bigtable are pretty simple.

1. MongoDB is not complex, the driver structure sucks.

Example Go's mgo driver by Gustavo Niemeyer was simple and effective, but abandoned. The official drivers is unnecessarily complicated. And Go's need to have "context" everywhere adds to this, but MongoDB is not complex. Idk I'm not some super genius and picking up MongoDB was really easy. Querying (aka aggregation pipelines), you have to think of that as "pipes in bash". It's in the words aggregation pipelines. find | groupby | sort | filter | select. Something like that. It's not SQL it's different, but not complex, sorry.

Simple indeed, they don't even offer anything that matches SQL flexibility.

Exactly my point. If the argument is to avoid unnecessary complexity, then how come a SQL database is the better choice?

Because not having proper query language turns simple wishes into complex solutions.

But it does have way to query, if you of course only know SQL and didn't bother to learn the MongoDB way to query then for you, the uninformed outsider, it might seem complex. But so does ArangoDB or Neo4j or GraphQL.

Like, if you were never exposed to rxjs and are now trying to build things with it doing

  $stream.pipe(
    switchmap(),
    filter(),
    etc(),
  )

It does seem more complex than

  stream.map().filter().etc()

but it's only so because you haven't put in the effort to learn that way.

Sure, whatever.

Now write DBA scale ISO SQL 2016 / Transact SQL / PL/SQL in that interesting Mongo flavoured language, including database engine debugger integration, and JIT compilation.

In what context? A hosted database might be "simpler" to operatoe, but BigTable is quite complicated and does a lot of complex, low-level, work to be very fast.