If I could see into the minds of major political leaders of the past, Hitler would be one of them. So would Lenin, Churchill, Lincoln, Andrew Jackson, Rasputin, Marie Antinette, and a host of others.
But it’s a bad look to lead with Hiter, and without LOTS of prefatory disclaimers. He only had a few.
During WWII the OSS commissioned a psychological profile of Hitler by Walter Langer. It was later declassified and published in 1972 as, "The Mind of Adolf Hitler." It does make for some interesting reading if you can find a copy.
I think I would pick Aristotle, Livy, and St. Peter. Interpreters to be supplied, I assume. I would ask Aristotle about Greek history, philosophy and science, Livy about Roman history, and St. Peter to fill in the gaps in what we know about the life of Jesus and about the early years of the Christian church.