[megameter]

You did all that in a few months? That actually sounds like something that went quite smoothly. The time needed to engineer that kind of high-scale system at the outset is also going to enter the multi-month range, and with less background info to inform it. The phase-shifts of scaling are by no means easy, but they respond well to effortful, issue-by-issue grinding away at the problem.

The worst-case overengineered projects generally have organizational issues that preclude ever making concrete progress or result in a Juicero-style "why did you even make this" product. Those are the projects that burn people out.