Request: Pass modifier keys

I'm trying to come up with a list of mappings to allow me to use the numeric keypad in MacOS as I do in Windows, at least in VS Code. (I code on both platforms daily, and I've been using the numeric keypad in Numlock Off mode since the IBM XT days, I've never been comfy with the "inverted T" arrows.)

I've remapped keys 1,2,3,4,6,7,8,9, and 0 to their arrow-equivalents, along with the same keys for Ctrl and Shift. But there's also Ctrl+Shift+key, Alt-key, etc.

For this sort of situation, where we're basically just swapping one key for another, it would be spiffy if there were an option to map the bare key and "passthrough" all modified versions of that key to the destination key. Obviously this only makes sense where the action is a keystroke, but where that is the case, it would cut down significantly on the number of triggers needed to swap a key.