Usually the way it’s done is that Rebbeim make the endorsements as “private citizens.” I’d assume that most dati U.S. citizens living in Israel would vote for Trump, because they are voting on a single issue. I personally am not voting for him because he’s a contemptable and vile human being. (Doesn’t really matter one way or the other; my home state is solidly blue, and would never become a “Trump state.”
BTW, I first voted in a Presidential election in 1980; this is the first time that I’ve ever voted for the Democratic candidate. I did not vote in 2016, because the choices from both parties were terrible. God save America.