just don't have US/Israel passport or visa stamp from there, and Iran will be one of best experiences in your life. people are amazing, culture is just WOW, whole place feels ancient even to europeans (and it is...). it is properly exotic in some parts in a way that will soon be only a thing of the past for most 'exotic' places on the earth, that look more and more like a standard copy&paste westernized locations.

most people speak OK english, very welcoming and friendly. don't trust some crap propaganda.

You need a certificate signed by an Imam, which you can likely get at your local Islamic center. Challenges include convincing the Imam that you're not just getting it to sneak into Mecca, and being able to answer follow-up questions at the roadblock in Mecca, such as, "So you're Muslim, eh? Tell us the Five Pillars."

I would guess that it will still work but at a (noticeably?) lower quality

The area around the White House is intentionally pixelated. Israel does not allow detailed maps in certain places - GPS navigation devices don't work there.