My apologies. I was quoting you from the forum. Just to clarify that I did not invent it out of the blue.
I am using Karabiner Elements to enable the Hyper Key and have no problem with the USB Device Key trigger, so I suspect it is something else blocking it (or some other interaction).
In fact the question is more complicated. I did not delve deeper because I did not want to bore forum members, but this may interest you.
I created a small macro (display hello) with Option2 as a trigger. I often switch keyboards US, german, etc
If I type Option 2 with the german (but no the US) keyboard BOTH the native Opt-2 and the KBM macro Opt2 are triggered, (quotes + display hello) (**) so the idea that KBM shortcuts override native shortcuts is not universal which is why I posted my question in the first place and asked if it could be solved by somehow reconfiguring the key with karabiner.
** If the opt 2 macro is simply to insert (paste or type) test, the both the native opt2 quotes and the macro text are displayed side by side.