While it is true that lots of presidents have had lower approval ratings at one time, Trump’s average approval since starting (39%) is easily the lowest on record, which dates back to FDR. That’s because the highest approval that the other presidents you’re referring to had were in the 80s and 90s, whereas Trump’s has never reached above 45%.
projects.fivethirtyeight.com/trump-approval-ratings/
This site shows Trump’s approval ratings based on the days in office compared directly to other modern presidents.
This site shows Trump’s approval ratings based on the days in office compared directly to other modern presidents.