Oh-Bee My response was mainly directed to the last sentence in your post, which seems a bit demanding, and I bet you are using Exchange or some other proprietary or commercial product or service, and now you want to switch to Mailcow, not because it’s “free”, but because it’s “gratis”.
The latter is simply a misunderstanding. FOSS is not “gratis”, you pay with your time or often with a support contract if you need reliable SLAs.
Mailcow is open source, which doesn’t mean that the project or the community around it owes you anything. A repo where they make the code available would be more than enough to comply with any of the FOSS software licences they use. Anything beyond that, like documentation or support forums, is done on a voluntary basis, and you have zero, none, nada claim to it.
Of course you know this, and that’s why you casually mention that you won’t use it if you don’t get reliable free support for it.
But guess what!? We couldn’t care less. The project and the community have nothing to gain from you using it. In fact, the opposite is true for users who just demand things and don’t contribute anything.