Oscar Isaacs is white, as are most Latinos, it's just a weird American thing that they believe the descendants or Northern Europeans and Southern Europeans are a different race, because history doesn't go back very far for most of them.
Similarly, Dev Patel is Asian British, born in London, and raised Brtish. Despite his dark skin tone, he is both from the right place, and, since Asians are actually Caucasian, the right race, so I would definitely say he looks tha part, just unusually tanned, which isn't unheard of in Britain.
The fact other roles are played by Australians, who might be closer looks wise, but are from a different (if closely related) culture, as well as the other side of the planet, certainly makes for an interesting thought on what constitutes appropriate casting for the role.
It brings to mind the argument Samuel Jackson made on hiring a Black British actor as the lead in Get Out, which he believed was inappropriate casting, since despite sharing African heritage, African Americans and Black Britains have vastly different cultural backgrounds.
Infact my only reservation is due to the rise in woke casting, using bigotry to cast roles based on appearence over talent. That's harder to justify here, because Dev Patel is a very talented actor, and Asians continue to be under represented in media, particularly in Britain, where they outnumber outnumbered all other ethnic minorities combined, but are vastly outnumbered by Black actors and actresses in the media.