This is a subject that personally find to be very interesting. I recently have read two books on this subject.
For decades I too accepted the story of Hitler's suicide as the final answer on the subject, and never really gave it another thought. But like a lot of things, I never really looked beyond the accepted story. Until recently.
Bottom line: Hitler's body was never found. Joseph Stalin firmly believed that Hitler escaped, and was never convinced otherwise. The US Federal Bureau of Investigation spent a lot of time and effort pursuing leads that pointed to the fact that Adolf Hitler survived the war and fled to South America.
It's not really crazy conspiracy theory. There is evidence that Hitler may have survived. The FBI documentation is there. It is not fake.
Is the evidence strong? It is neither stronger nor weaker than the 'evidence' of his suicide. Today if you are a prosecutor and want to convict someone for murder, you need a body. Hitler's body was never found, neither was Eva Braun's.
As for 'testimony', or 'eyewitnesses', today one needs to take them all with a grain of salt.
Think for a moment, if you were a dedicated Nazi in 1945, or 1946, or later, the greatest secret of all would have been your Fuhrer's survival after the war. you would have done anything, said anything, to throw any potential pursuers off his trail.