@benjamineskola @gme no lock-in involved. I proposed several solutions and they decided they want OpenBSD as they're already using it for some services (mainly ssh and VPN endpoints) and they appreciate it. Their internal IT staff is able to manage it on their own, at least for basic stuff.
Mailcow is nice - I'm using and installing it when needed, but it's another "product". Having different components involved means being able to replace them individually.
But yes, I can understand your point of view and you're not wrong.