Bianchi has been really subtly running a sexual abuse subplot on her character - she often kills all the men she dates and has been interacting with both romance and death as punishment from such a young age that it’s what she built her entire identity on, enough to become prolific - but actually getting confirmation through chronology she was a famous femme fatale going after her partners at 14/15 is another thing altogether
and reborn was her closest companion during this period. this man was an unconscionable asshole from the manga’s outset and didn’t start a redemption until he went into the world where everyone hyperdied, but it’s so hard to comprehend how firmly his politics meshed with people like iemitsu.
think of how important it was that it was tsuna who earned rokudou “my family was hunted down and shot in the streets and they all decided to mesh even more tightly with shitty mafia politics to get themselves out of it” mukuro’s trust. reborn would have killed him, with contempt. tsuna bought the trust of every single member of that group who wasnt a serial killer
reborn’s “I thought I’d die like a dog” isn’t manly nihilism, the context reads like “that’s just…….how it works kid”. he’s spent years like this. he’s old as hell. the reason he suddenly opted not to just die like he feels he’s meant to is because tsuna said “no it fucking isn’t”, because he wasn’t groomed into this situation. this is the same arc where reborn violently prevents iemitsu from using the same techniques he himself utilized during the daily life arc to “teach” tsuna (and implied to have used when training dino), and instead appealing to tsuna’s character and values.
in fact, the reason this series has so much integrity even though the writing is a garbage fire is because tsuna, someone who has never encountered most of these issues, has values that counteract them - he doesn’t say shit to mukuro, there is no shounen lecture, but mukuro spends a huge portion of the rest of the series putting chrome “mukuro projecting all of his insecurities onto a confused dying girl” dokuro in the hands of tsuna to the point chrome calls him on his genuine love for tsuna, she outright says it to his face, because tsuna isn’t and never has been someone who could be told about any injustice in the mafia without him reacting with genuine contempt and action. If you told sawada tsunayoshi that when bianchi was his age she was seducing adult men and no one - not even reborn - ever saw anything wrong with this he’d show up at everyone’s house to negotiate a nation-wide re-organization of the assassin circuit and make the vindice help him do it.
I think the most outstanding example of this mindset is a set of 2 events, where tsuna is told that to become the vongola boss, you need to accept the injustice of the mafia, and he, a regular 14-year-old civilian, said “are you KIDDING, this is an INFRASTRUCTURE YOU HAVE”, and threatened to destroy it with such conviction that it proved his right to be leader. it was a hype moment, to be sure
but then in the Simon arc, Tsuna goes up to Nono’s face and says “I can’t take this position, because the mafia is a garbage concept, and it directly endangers everyone around me”. Tsuna wants to crush it, and is aware that leadership is the best place to start, but he’s also aware that it’s a phenomenon that eats the people that interact with it, and this happens in the arc where a literal ghost manifestation of the mafia is trying to kill everyone and possesses the only staunchly anti-mafia character to do it. The message is pretty obvious
Maybe the ending is justified under that - nothing about tsuna has changed because even after all the things that tried to warp him as a person, he maintained the mindset that let him deny the values of the mafia and in turn change what they consider normal, and build trust through that understanding.
The series has a clear through-line in its narrative that really holds it together and is never made obvious and proves the need for “Dame-Tsuna” as its lead and that’s kind of great???