I have a relatively terrible answer that I would recommend to no one but it works for me. That's the fastest stack for me.
The question wasn't "what is the fastest stack" or "of all stacks which is the fastest for you" but rather akin to "what is the fastest stack for you". Which is often the one that you are productive in.
It's almost always not worth learning a new stack to prototype something unless the goal is to learn the new stack.