I am very familiar with Micro$haft's monopolistic behavior and corporate treachery - I have been dealing with it since they had their undeclared war with Linux back in the 80s. The problem is that they bought Xamarin and are in the process of killing Mono, which has been my operational basis. Killing Mono is what the community expected when the Gates monster bought Xamarin, they just have been a bit slower about it than expected. If the community picks up Mono support, maybe it will remain "alive," but for now support is basically impossible to get.
Since I am a C# programmer, I hadn't thought about the support for the other languages, but my understanding is that the runtime covers all of the languages. According to
this link, Ubuntu now has runtime support for .Net 6, which is why I dragged the subject back out from under the bed. I have downloaded the runtime, etc., and am in process of trying it out for my programming needs, but since Linux is where I live most of the time, not having yWriter is a pain, to put it nicely. I am still stuck using Visual Studio for heavy programming, but I can do that on a VM. Since Windoze doesn't play nice with VMs, it is very frustrating to try to work, both in Visual Studio and yWriter, when I am under the VM.