American CEO instead of Taiwanese American

Consider that most people born outside of the USA are not eligible for military clearances despite being US Citizens

In this respect, the DoD would likely prefer the most “American” company possible, I.e with buy America provisions.

Mostly marketing/branding, but also that AMD is using TSMC of course.

If you asked someone not in tech "which one is american" out of AMD and Intel, they would say Intel; despite the "A" in AMD literally standing for "American"...