I like to see it as two very different people who had prejudice views against each other especially the white guy. But they then realized the differences they thought they hated were meaningless and grew to love each other despite their differences. Everyone interprets things differently though.
Any watch order would be fine, but gun to my head I’d say Moon-> District 9 -> Arrival -> Ad Astra. Ad Astra is also a WONDERFUL movie to be high for, it has some of the absolute most stunning visuals I’ve ever seen in any movie. I’ve got tons of other recommendations similar to what I’ve already suggested if you’re interested