Also, Unity is in C#, with some reluctance I figured "may as well try writing the supporting API server using C# too." Partly to see what it would be like, and partly to keep it all consistent.
So far the entire process has been very pleasant? Visual Studio is working pretty well. NuGet comes with all kinds of packages natively / professionally supported by Microsoft. All this MVC scaffolding is done automagically. You can stand up a full REST API with database integration in minutes. It also supports Docker / Linux natively apparently.
Has anyone had this experience, or is there some nightmare beyond this garden path? Is it possible that Windows / C# / ASP.NET stuff could be becoming more viable for web?
As for "is it good"... it uses less memory and is faster than any interpreted language currently in use for web development. And, as you have noticed, deployment using Docker containers is possible everywhere Docker is supported. Surprisingly, AWS supports the current runtime of .NET faster than Python and Node (though they also drop support for .NET versions sooner than out-of-LTS versions of Python and Node).
It also boasts a large and active developer community, ensuring ample support and resources. Additionally, its integration with the Microsoft ecosystem further enhances its appeal. Overall, .NET remains a strong contender for web development, offering a reliable and efficient platform for creating modern web applications.