Gohan got angry and unlocked his hidden power. SS2 was his hidden power. You are looking far too deep at what is very surface level.
It obviously wasn't temporary against Cell, since Gohan had a complete change of personality. It seems that SS2 maintained Gohan's rage boost.
It didn't maintain his rage boost. His rage caused a transformation, end of story. He was overflowing with power and riding a wave of emotions, he got caught up in it. You inferred wrongly that the transformation changed him. It only did so indirectly. I didn't even change his personality forever. He goes back to who he usually is when Cell is about to explode, but he still stays SS2.
No, there is the story present in the manga, the story present in the anime, the story present in a video game, etc. There are many alternative takes of the story, Toriyama's story is just the original one. No matter how you slice it, there is no official canon.
No, there's just Toriyama's story, he's the author, ergo, his story is canon. An anime adaptation doesn't supersede the author. What are you even getting at? If someone adapts the work of the original author, there's no longer an official canon? That makes NO sense whatsoever, there are different takes, but one official take, the one written by the original author. The Sherlock Holmes stories written by Sir Arthur Conan Doyle don't cease to be canon just because his character is one of if not the most adapted character in all of fiction.
Vegeta even sees SS2 Gohan's power, says that it was far bigger against Cell and that he is stronger than him now, but there is no telling what would happen if he had gotten angry. Daizenshuu 2 even states directly that SS2 Gohan was weaker both because he didn't train, and because he couldn't get power from his anger. There is no debate, it's been made very clear that Gohan got SS2 + Rage Boost against Cell, and he could only turn into SS2 in Boo arc easily, but couldn't get a rage boost on top of it.
You are inferring what you want to. Gohan got soft, that's it. I don't count the Daizenshuu, it's not the original work. I'm going purely off the original work. The fact that Gohan couldn't get stronger due to rage at a different point in the story doesn't mean that Gohan experienced another boost on top of what was already a considerable boost from the transformation in the Cell Games. It doesn't make any sense. Why complicate things by having Gohan transform and then get a boost on top of that? The transformation was the boost!
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