Not sure I can help but let’s try:

If you have iOS 14 or greater you can connect a bluetooth keyboard to your iPhone and then “maybe” write a shortcut script with the command key you need to use.

Look at: Settings | Accessibility | Keyboards | Full Keyboard Access(allows external keyboard access)

There are “Commands” that can be customized but I don’t think thats what you are trying to do.

I think your best bet is to try creating a shortcut script to do what you want and that would only need the external keyboard when configuring the actions you want to take.

Good luck.