In the first few episodes, why was so much effort put into Wegener passing the blueprints to the Japanese Science Minister personally, repeatedly putting him at great risk? Why couldn't he simply give the blueprints to Tagomi, who could then pass them to the Science Minister?
Why didn't Joe shoot the Yakuza boss? We know that he had no more bullets left, but he couldn't possibly know that about a gun he saw for the first time, could he?
Well, he is a gunsmith, so it's likely know the weight difference between a loaded and a unloaded weapon.
How did Heusmann's plan get as far as it did? Hitler's access to the film reels seemed to keep him one move ahead, did none of the alternate realities he was seeing show Heusmann for what he truly was? I mean even if those films only fell into Abendsen's hands everyone loses if the Resistance sits on the information.
The films that are collected give you information about alternate realities, but not all of it can be relied on. As The Man in the High Castle notes, some people are always the same, no matter the reality, while others are very dependent on circumstance. It's also worth noting that the characters are putting together clues from what they have. Film reels of a documentary on how the Battle of the Bulge went is easier to interpret and more useful than a Fourth of July celebration in the 1960s. There might not have been anything that provided a vital clue until after Hitler died of natural causes.
We can presume the reels only show footage that would realistically be taken in the timeline they originate from. There could plausibly be reels of Heussman giving a speech or a German-Japanese war, but Hitler wouldn't have any way of knowing that they would result from Heussman assassinating him.
Amazon's promotional image for the third season is a flag with what looks like some kind of Peace Symbol on it; the trailers and other promotional material associate this was the new resistance that begins in season 3. This makes sense, since it's the symbol for Himmler's secret Lebensborn corps, but inverted. The trouble is that while the new resistance selects a symbol to represent themselves, it's the "Sun setting on Kido" icon that Frank created; the inverted Lebensborn flag doesn't appear anywhere in season 3. On the other hand, it isn't tremendously surprising given that only very high-ranking people in the fascist forces or the resistance can move freely from coast to coast, and the lack of a free press to disseminate resistance images and memes, that the US East Coast anti-Nazi Resistance might select an additional symbol additional to or in stead of the anti-Japanese one Frank made.