F# is less popular, but it’s a first class .Net language with full MS support and integration onto .Net (VM and ecosystem). C# has been tracking F# and aiming for language parity for years (ie all your modern C# devs should be learning the same language facilities). F# is multi-paradigm so C# devs can write idiomatic C# with minor forced changes. And as a .Net language you can always decompile it into C# and keep going from there.
That’s a radically different proposition than, say, raw OCaml and not particularly niche. It also impacts hiring pools differently since competent functional C# devs are viable, but it tends to appeal to a certain calibre of dev.
Moving faster with fewer errors and more talented candidate pool are relevant to repackaged SaaS startups too. Leaves more time for the other stuff and scales better.
Last I knew, Rider was pretty much the only IDE available for a large codebase when you weren't on Windows. Much love for Ionide, but it was a serious struggle.
Is this any better now?
Our scenario: relatively simple monorepo, lots of docker, just enough bash, trunk-based dev strategy. It's great for that.