I do know Germany had developed a New and Greatly improved U-Boat at the end of the war. Can’t recall the name. But it used some sort of Hydrogen Peroxide propulsion so it could stay under much longer. Was also more stealthy. So I guess it’s possible he might have made it.
Personally I believe the reports of the Fuhererbunker survivors. He shot himself and they burned him in a pit with petrol in a garden behind it. The Soviets even identified his teeth I think?
Yes, the Soviets — first to enter Berlin — found his charred remains. The jawbone was intact and was easily identifiable by the dental work. (Hitler had notoriously bad teeth.) The bones were taken back to Moscow; I don’t know if they’ve ever been examined or authenticated or even displayed.