> They slice and dice the org until the 30 people become split into teams of 2-3 with a manager for each, running into coordination hell on each step

This is the key mistake. Having teams of 2-3 with a manager each is way too many managers. If you have a clear focus, small teams are great because they can work autonomously, with little management and good results. You can't hire your way out of coordination hell.

I was at WhatsApp between 2011 and 2019; for the most part early on, we had essentially the CEO who does a mix of product management and engineering management and engineering, an actively engineering server manager (who also did some client work), and a client engineering manager. Android team grew enough to have an engineering manager and we also ended up with one product manager. Post aquisition, staff grew and so did management.