On: I stopped everything and started writing C again

[p_ing]

There are at least a few kernels, bootloaders, and device drivers written in C# out there… granted for hobby/research.

https://github.com/Michael-K-GH/RoseOS

https://vollragm.github.io/posts/kernelsharp/

https://www.gocosmos.org

https://www.microsoft.com/en-us/research/project/singularity... (asm, C, C++, largely C# (Sing#))