AFAIK Janet is not "much simpler to interface with C++". Janet has good FFI for C, but not for C++ directly. Janet's native FFI system is designed specifically for C libraries. C++ has name mangling, classes, exceptions, and other features that Janet's FFI cannot directly handle. The process would be similar to using C++ libraries from any C-based language, which is far from straightforward.

Jank, if my understanding is correct, in comparison has direct C++ interop. Jank treats C++ as a first-class compilation target rather than a foreign interface.

It shouldn't be that much work to wrap a C interface into C++ but yeah Jank is probably the way to go if it natively supports C++.