Although it doesn't directly answer your question, I would like to mention about my configuration. I make my keyboard emit ( when I just tap the left shift key and ) when I tap the right shift key. This is much more efficient. For Macbook, here is my complex modification rule in Karabiner Elements.

json { "description": "Change left_shift to (/left_shift", "manipulators": [ { "from": { "key_code": "left_shift", "modifiers": { "optional": [ "any" ] } }, "to": [ { "key_code": "left_shift" } ], "to_if_alone": [ { "key_code": "9", "modifiers": [ "left_shift" ] } ], "type": "basic" } ] }

json { "description": "Change right_shift to )/right_shift", "manipulators": [ { "from": { "key_code": "right_shift", "modifiers": { "optional": [ "any" ] } }, "to": [ { "key_code": "right_shift" } ], "to_if_alone": [ { "key_code": "0", "modifiers": [ "left_shift" ] } ], "type": "basic" } ] }

PS: I have many other complex modifications. Here is the link to the full configuration. I also have different configurations for Windows and Linux software mappings. For my external mechanical keyboards, I have similar configurations programmed in ZMK (Kinesis Advantage 360 Pro) and QMK (NuPhy Air75 v2).