I'll help deal with any issues that may occur. Just post them here.
There is no MacOS version. I’m assuming you’re using Wine or something. I actually had forgotten to add a note in game about this, but the “select key” is X. It also says so on the game’s page.
EDIT: Just saw your edit. xD
Try unplugging it (leave it unplugged) and open the controller config again. If it says "controller not detected" or something along those lines, then it's a compatibility error. Otherwise, it means you have something else the game is mistaking for a controller connected. Unfortunately I don't have that controller, so I can't fix it if it's a compatibility error.