> Given that our deployment platform was Linux (for a .Net Core 3.0 project), I was determined to use Linux and VS Code for development. That was a fail; the verbose nature of C# and the Framework APIs make it impossible to be productive without significant help from a full-fledged IDE like Visual Studio.

I have had and continue to have the opposite experience of you. I use Ubuntu with VS Code and a few C# plugins that have greatly allowed me to navigate the .NET Core framework and write code with minimal references.

Even, with Visual Studio (unless you use R#), you will always run into issues where you aren't sure where the function or class lives. That's why you go read the documentation or ask SO.

The more you write webapi's the easier it is.

> Structural Typing

Dynamic was the closest to it, but it has significant performance issues. Tuples and structs do exist also.

> Allow functions outside of classes

No.

> Verbosity in C#

????

> most popular libraries will nudge you strongly to use Dependency Injection throughout the app and implement everything as a class and to extract interfaces out of it.

You do realize C# is mostly a strong Object Oriented language hence why they (the libraries) urge you to do that.

If you want functional so much use F#.