Is it possible to turn a Gamecube controller into a stick?

I’m just wondering.

Yes. You break open your controller and you take out the PCB (Printed Circuit Board)

You then get wiring and buttons and a stick along with a case.

After that you solder the wiring from the buttons to the correct place on the PCB.

That’s it in a nut shell but you will want to do some research on it. is a good place to start.