How do you then give say 20GB of test production data in a packed structure to ML? Re-write thousands of lines of C++ infrastructure into another language just

How do you then give say 20GB of test production data in a packed structure to ML? Re-write thousands of lines of C++ infrastructure into another language just to test it in this "theoretical" language? Or re-use the existing code and write a slightly hacky prototype within the code which can close to effortlessly run any data the program creates/accepts. I know which one I'd pick.