It may be debatable, but I would say C++'s template syntax is not nicer. I do not think working with void pointers is annoying, but I also prefer the container_of approach. The ## certainly has the limitation that you need to name things first, but I do not think this much of a downside.

BTW, here is some generic code in C using a variadic type. I think this quite nice. https://godbolt.org/z/jxz6Y6f9x

Running a program for meta programming are always a possibility, and I would agree that sometimes the best solution.