The market is so bad, and most interview sucks one way or another. The main reason is interviewer have tens or hundreds application for same position.
I have just went through one interview that have 4 rounds.
1. half hour talk
2. 2 hours coding for several crud api.
3. system design project ( I spend 2 days on it. they told I have about a week on it)
4. another half hours with CTO.
and then got rejected. (The interviewers does not bother to send a reject letter. I asked them they told me the position is closed).
In theory, you could write dbt in make. Actually, Whenever I introduce to others about workflow concepts (DAG), I tell them it is similar to how make works.
I don't think they need 100 more current connection. Assume one process take 1 connection, only several connection are required.
I think there must be some misconfiguration there. otherwise, the throughout should not be that low.
If possible, the author should setup a demo (contrived query, but similar to production scenario). From there, others can give valid suggestion or improve the code and configure.