Obviously this administration is seething with Israeli and Jew hatred. So the best thing Israel can do is to first set up a reliable “shadow diplomacy” network with those outside the administration who are sympathetic to Israel and Jews.
And then pull the credentials of the US ambassador, as well as others manning the US embassy who are engaging in or supporting hostile activities. Then create a ban to the entry of other hostiles from the US.
Specifically those Jews who engage in anti-Israeli or anti-Jewish activities. Inform them that they are now banned from travel to Israel, for any reason, even if they claim dual citizenship.