If you nativize a blueprint and peek its underlying generated C++ source code, it is unreadable (I think you have already seen it). So I doubt that there is a way to further make it readable by human by manual editing it.
It is more productive IMO, to just convert manually the BP to C++. Many spaghetti BP nodes can be converted into a few lines of C++ code, so it quite easy. And also, if you are not sure about the corresponding C++ BP node, you can always right click on it and select Go to Code Definition (but not all node has this though… lol)