re: Tyson Fury is the most unbeatable boxing champion

Not so sure about that. I think someone like Vitali Klitschko would give him problems. Vitali had an Iron Chin, height, an awkward lean back style, could anticipate punches almost like he knew they were coming and had plenty of stamina. He only lost due to injury twice (both times he was ahead on official scorecards) and was never behind on any scorecard after two rounds his whole career.