I don't have any good answers for you re building a community as usually people will only come if there's money. So if you could create some kind of marketplace where customers could ask for things to be built and then devs could build and make some money from it then that might work. But starting a two-sided marketplace is hard ... or so they say.

But I mainly wanted to comment and say I started learning F# recently getting a bit into Elmish and think F# is a pragmatic language and would love to learn more but there is a lack of large F# codebases to learn from. So would be interested in taking a peek at how one would construct a large F# codebase targeting the enterprise if this does ever get released.