It's not malice. Your non-technical boss who says "well, if we have 3 other developers developing that API with you, it should get it done in one fourth of the time, right?" is not malicious either. But this kind of a boss doesn't "get" it, and neither does Microsoft. They don't seriously understand the mindset behind an open source project, and I don't expect them to in the future either.
So I avoid all Microsoft technologies, especially the lock-in ones like Visual Studio and .NET. I recommend you do as well.
There is nothing "lock-in" about .NET Core/.NET 5+. In fact, as you can see from this whole Hot Reload kerfuffle, even Microsoft themselves doesn't always like the spirit of open source present on their own .NET team!
.NET Framework is another story, and was (and still is) tightly coupled to Windows. It's the entire reason .NET Core was started as a separate open source effort. Honestly, we're lucky .NET Core was even allowed to live as long as it has. Now, it's philanthropic culture is directly butting heads with the profit-oriented culture of the Visual Studio team.
That's the thing – I don't understand why people will chain themselves to caring about all this when you acknowledge that “Microsoft themselves doesn't always like the spirit of open source present on their own .NET team!”
Does .NET have some breakthrough features or support that other languages don't have? Are job opportunities better than, say, Java?
I'm not understanding the upside here of following the Microsoft version of Keeping Up with the Kardashians.
So I avoid all Microsoft technologies, especially the lock-in ones like Visual Studio and .NET. I recommend you do as well.