For the function keys of F 1~ 12, by default, when pressed alone, the MAC turns on the adjustment function, not the basic function. To achieve basic functions, you need to press fn on the keyboard at the same time. This is why pressing F2 is not the function of F2, but the brightness level.

When applied to your problem, change the shortcut key back to F2, and then press fn+F2 at the same time to realize the function you want to achieve.

As for setting other shortcut keys ... because the MAC comes with many shortcut keys, if the shortcut key you set conflicts with the shortcut key that comes with the MAC, there will be no response. The best way is to use the default shortcut keys of PS to adapt and get used to the new shortcut keys.

I hope it helps you.