how to "send keyboard shortcut" only one modifier key?

I have an app in which the function can only be triggered with holding down a modifier key. I want to use "right option key".
So I wanted to make a Trackpad trigger "3 finger tap/click" that then actually triggers the right option key so that this triggers the function of the app. So basically, I want to use my trackpad and not the keyboard.
I really searched the web for hours, but there seems to be no possibility that a you can trigger only a modifier key (with permanent push down) and nothing else. Even in the modifier key options, there is always "option + key down" oder something like that. Is there any way to achieve this? This drives me nuts

You can try with the "Right Opt Key Down / Up" actions. Best add a little delay inbetween. However apps that trigger when holding a modifier might be quite special, you'll need to try whether it works in your case: