Still a lot of Windows baggage with C#. It's changing, but I think most c# devs are still learning fundamental unix and docker stuff. So you'll get an overhead with C# too, just not in technical performance.
Source? As a .NET developer I can tell you that there are plenty of us with Linux/Docker experience. There is zero Windows baggage with C# in .NET (Core). Your information is out of date.
> Projects making use of Sitecore, Dynamics, SharePoint, SQL Server CLR,
What projects? None of those are forced on you or have any references to them built into .NET Core. I've been building .NET apps since 1.0 reached beta (in 2001?) I can count on one hand how many times in total that I've worked with those systems. This argument is a hell of a reach.
> GUI frameworks out of Redmond
The upcoming Microsoft MAUI is cross-platform (no, Microsoft isn't building support for Linux, but there are open source efforts working on it.)
Switched from a career of a windows/.net/c# to a max/ruby/js shop. Docker skills transferred. Had to learn Unix commands but it didn’t feel much different from cmd/powershell