I would say you are lucky. I lived in my college town for 20years and it started out chock full of co-ops in the 80s and by the time I moved away they were all hardly recognizable or gone. Food co-ops, housing co-ops, internet co-ops... all mutated away from shared labor or were replaced by sole ownerships.
My wife works for an employee-owned engineering company, but they are anything but FOSS in their culture.
I hope these intermediate management structures that combine expertise and collective ownership grow more. But it still isn't a slam-dunk that should be assumed to be the stupidly-obvious approach unless such organizations compete with the grifters... and then their success won't be due to the fact that they are using FOSS but that they present a track record of success as an organization.
I will just say that I think mermaid is great. I use it via the DiagrammeR package in R and via Quarto. In addition to manually typing in diagrams I sometimes write ad-hoc code that helps me visualize my data (and source code) by emitting one of the relevant mermaid syntaxes.