All this multiplatform stuff is bullshit according to my experience. The dotnet CLI is slow, files still use CRLF line ending, I also remember CLI autocompletion was not great. C# has only one working LSP server implementation that sucked ass in VS Code and Neovim. It's kinda like Java DX, but at least with Java the DX is equally isn't great on any OS. Maybe I like C# more than Java as a language, but I hate everything else. I also hate Java, btw.

Also .Net wasn't always OSS, therefore it has proprietary history (Java has less of the same).