How do I claim rewards on XBox Game Pass?

I can see a Great Zimbabwe Wonder reward on the website, I click on it and can see that Steam and Epic are linked, but Game Pass is not.  A tooltip comes up saying the link is required, but I can't find anywhere to make that link...

With all the gripes I've had playing through Game Pass, this all Feels half-baked and that I'm treated as a second class customer.

Bump, anyone know how?

Why isn't this a thing? I am only now learning that buying the game through the xbox store was a mistake?