show function keys per app - (not) supported?

i know the option with Fn to display the function keys in the touch bar, but i don't want to press Fn all the time in some apps that use function keys in particular, and i don't want to put the touch bar on it just because i use Ink-Scape - that's not why it was invented...

I was convinced that BTT could do it... it's so easy, I thought, that goes without saying.
But after searching in BTT and finally here I only found answers from the questioners themselves: You use another app for that (fluor... Is that correct: BTT doesn't support this switch to function keys as a static action per app?


I am having the same problem. I wanted to do the demo to Xplane Flight Simulator, since Microsoft Flight Simulator is a PeeCee-only game.

But X-Plane needs function keys to fly the plane. Any ideas how to get the function keys to appear when X-Plane is the active app?