However, the build/package system for this is still a complete mess if you want to target more than one architecture; I've spent much of the week looking at the question of how to make cross-platform assembly A depend on platform-specific assembly B, where B is one of B-win or B-mac, and it seems to require carefully hand building B into a nuget package.
I'm coming to appreciate msbuild, though. Or maybe that's Stockholm syndrome.
I think making it open source has come with a cultural change that's still propagating. It means not just defining the "Microsoft way" to do things but coping with myriad use cases turning up in the issue tracker.
Using XML as a general purpose programming language is also very ick.
It gives you the same IDE experience for your build scripts and your code including REPL for experiments and a debugger when needed.
since it is .NET Core they are as cross platform as your other code.
Actually it was already there in J++, and now we have Oracle trying to add back what Sun killed in 2000, with keeping 26 years of history running, it is ironic how some things turn around.
I think the big downside is that the industry still thinks of .NET as stuck in .NET 2.0 or something, from my casual browsing that .NET is a skill not C#. Regardless, I'm getting kind of excited for .NET 6 on official release, and doing the migration of all our apps off framework to the latest and getting some getting the new lang version.
If it is the former I can say that I never ever built on top of Sitecore or SharePoint. Recently only Asp.NET Core or whatever it is called now.