There’s some evidence to suggest that Hitler’s decision to commit suicide was influenced by the news that Italian partisans captured and lynched Mussolini and his mistress.
He had announced a week earlier to his closer associates that he would stay in Berlin and kill himself if the city wouldn’t hold. But nonetheless, within less than a day of learning of Mussolini’s fate he did the deed. He was also in a very unstable mental state during that week, going on tirades about the worthlessness of German people, how he was surrounded by traitors and cowards, and how they all deserved to be erased from history for their failure.
So it’s possible he’d had killed himself either way to avoid being lynched by a mob or to not confront the day after a German surrender, whether the Western Allies had reached Berlin first or not.
If the scenario you are talking about had happened, it’s possible he might have lived, but I still doubt it. Hitler had a much higher international profile than both Mussolini and Hirohito. To the average European, American or Soviet, he was THE reason for the war. It’s likely he would have still been tried and executed, especially as the attrocities at concentration camps had been uncovered and made public. It would be a very difficult task for the Allies to rehabilitate Hitler in the eyes of their own citizens, the world, and also the Germans.
Also, the Soviets would still have plenty of leverage to force the trials, particularly since it was agreed beforehand at the highest level, and they occupied territories the Allies were interested in, like Poland, Hungary, Czechoslovakia and Yugoslavia.
Japan is a different story, precisely because its own attrocities were never really part of the public discourse in the West during or shortly after the war. Some things, like Unit 731 did not become public until the 50s and 60s.



I’m not saying he was sad about it. He was scared he was going to get the same treatment.