Trump isn't into much of anything other than feeding his ego, his greed and his lust. That's another aspect of his fundamental childishness - his desires and motivations are very simple and sybaritic.

However, he's surrounded by people who are stroking hisxegovand whispering in his ear and trying to get him to focus his wandering attention on things they want, and some of them certainly are very much into eugenics. That is in fact an obvious and deliberate implication of replacement theory and pro-natalism - people like Musk see reproduction as a contest between races, and one that they're afraid they're going to lose and are determined to win, by whatever means might serve.