One of my favorite books growing up was the Scholastic Encyclopedia of the Presidents and Their Times by Dave Rubel. It had a profile of every president that included their "nickname". I had the 2004 version that ended with George W. Bush ("Dubya") but I imagine the polite, non-partisan nicknames for the subsequent presidents would be:
Obama: Barry
Trump: The Donald
Biden: Scranton Joe
Trump's is tough; "The Donald" doesn't really feel right. Admittedly, it's tough to think of nonpartisan, neutral nicknames for him, but even so, I feel like "the Donald" is (no offense) a bit too bland, especially given how...colorful and feisty his personality is.
Someone who unironically uses Genocide Joe gives us a good idea how seriously we should take them.
Something tells me that many of the people who use "Genocide Joe" will be silent when Genocide Donald indulges in the Israeli government's worst instincts.
Tbf, "Genocide Donald" really doesn't have the same ring to it that "Genocide Joe" does. (Once again, this has nothing to do with the facts of the matter and everything to do with how absurdly, weirdly funny the nickname is.)