Could you give some examples of the bloat they've added to C# that represent their "seriously screwed up priorities" aside from not adding Sum?
I understand that you shouldn’t always give users what they ask for - but this is something that has picked up steam in other languages because it’s actually useful and makes code bases easier to maintain.
I've used C# since 2008 for business software and high performance computing. I've not missed sum types at all. Most of what was added is something I see a lot of value in. I don't like that it, by design, obsoletes some older parts of the language, but that's about it.
I'm now using C# on linux almost exclusively. No complaints from me!