And while you can use anything for servers, even Microsoft refuses to use Windows Server for their own servers and uses Linux based OS, so go figure.
What else is there, your favorite flavor of BSD? Unless someone else already ported everything necessary, it will be a DIY project and you will be the one telling people about it.
There aren’t that many options that just work out of the box other than Linux, it’s most popular, and practically just works for anything you can imagine self hosting, of course people will be talking about it almost exclusively, because using something else is a pointless duplication of effort for what purpose exactly?
Ah yes, lists of lists is my favorite programming language.