I was recently at a Microsoft heavy tech conference and spoke to at least 50 .Net developers. Anyone who also did front end did so in Angular. I was surprised at how popular it is!
This fact about Angular doesn't surprise me. It uses TypeScript which is a Microsoft joint, and the architecture feels rather similar to the MS standard MVVM. Two way data binding in the UI, a "code-behind" in the component. And TypeScript lends a sort-of C# flavor to the framework. It takes some "enterprise" and puts it in the front-end, which can help make the transition from ASP.NET MVC or whatever to Angular a bit easier (especially as compared to something like React).
If you're already doing .NET stuff, and you need enterprise-grade front ends, Angular seems like the natural choice still. One thing about Microsoft shops (of which my employer is one) is they tend to use Microsoft for everything, and despite Angular not actually being Microsoft, TypeScript makes it close enough. I'll be curious to see if the eventual production-ready release of client-side Blazor changes the dynamic at all.