I have 2 rectangles, one which is basically the other scaled up, like so

I’d like to see if a set of xy coords falls within the XOR difference, ie

What’s the best math to do this?
Difference (XOR) between two rectangles, as rectangles? does kind of what I want, but not exactly, and it seems somewhat… inelegant.
Alternately, I could work with something that returns “true” if x/y coords are within 10% of the edge of the outer rectangle
where I’m assuming
rect1is the outer rectangle.