[dustbunny]

You likely won't need to do manual memory management nor think about undefined behavior. If your writing basic c++ to handle the simulation in a game, it's going to be pretty orthodox and these problems likely won't manifest.

The purpose of recommending c++ here is:

If GDScript is too slow, reach directly for C++.

I'm specifically recommending GDScript over C# for ease of use and c++ over C# for performance.