It was even before through mono/xamarin

What does fully cross platform mean? It sounds very vague and a lot like an exaggeration.

True, but what I’m really talking about is the unbeatable user experience of having an application that looks and feels as if it were a native Windows application, because it is and has that first-class platform support straight from the vendor.

With that said, most new cross platform applications today are probably more like electron or Web apps.

Not really, even GUI is going strong, check Avalonia UI.

Or realistically on Mac. Mac Catalyst is neat but you’re basically building an iPad UI and afaik that’s all that MAUI supports still

ASP.Net Core is a phenomenal backend.

C# development was spearheaded by Anders Hjelsberg, one of the brains behind Borland Delphi/Object Pascal.

Does it get a bad rap outside of this meme? I've only heard praise. It's by far my favorite language

I've used many languages/platforms in my 30 years of programming (take that!), including Visual Basic, C, C#, Java, Objective-C and C++. I agree that C# is the best but not by much. They all do pretty much the same things - if one language lacks something that other languages have shown to be beneficial, that something tends to get incorporated in a future update in some form or another, and their glaring weaknesses tend to get corrected as well (like when Objective-C mostly did away with the need to explicitly release fucking everything).

I'd argue we aborted before it could be born into mainstream

What do you mean? The entire stack is open source.

TypeScript?

It is Microsoft JavaScript.