I can think of MonoGame and Stride as examples/exceptions, though I suppose there are more out there, including peoples' own engines. Most popular engines that

I can think of MonoGame and Stride as examples/exceptions, though I suppose there are more out there, including peoples' own engines. Most popular engines that expose a C# interface officially or unofficially take the other route. But I grant you that the oft-given reason for this - performance - isn't impossible to achieve with pure C#, it just takes a lot more skill and knowledge, and that performance via native calls to a C++ engine aren't always more performant anyway due to marshalling.