I'm _really_ disappointed with the managed DB service. The "75 simultaneous connections per gigabyte of usable memory" limitation means cost wise it's cheaper just to spin up a 'real' database droplet.
FWIW, if you’re using 75+ connections, it’s probably a good idea to add some kind of Postgres proxy in the middle like pgbouncer. Postgres doesn’t handle lots of connections well because each connection forks off its own full OS process, and the performance can degrade noticeably when you have too many connections to Postgres as a result.
This is the case for literally every managed database service that I'm aware of.
You pay a premium for the managed aspect.