Does Blinken hold dual citizenship with Israel, since I assume he is a Jew?
That I don’t know.
His family’s been into left-wing politics for decades; I can’t find what branch of the faith he practices, but safe to assume it isn’t Orthodox. His father Donald was Clinton’s ambassador to Hungary. Tony himself used to work for Obama of course. And there are strong ties between his family and Soros.
https://www.timesofisrael.com/where-blinken-stands-on-jewish-issues-from-immigration-to-israel/