I've heard it claimed that the expression "Shimshon HaGibor" (Samson the Mighty) [as a descriptive of Shimshon in Tanach] was invented by the Zionists, to promote their "strong Jew" narrative. Is this true?
The rumor is false. The earliest I can find the phrase 'Shimshon HaGibur' goes back to 1831, long before modern zionism or Hertzl.
It can be found in the book צמח דוד
Google books also shows other phrases such as Shimshon our Hero from books in 1801, but those are in English and not the exact phrase. I would not be surprised to find it occurring even earlier than that.