i respectfully disagree...
I don't have to explain my reasons, as I know this will just spark another discourse where both parties will get upset.
But the one thing I heavily disagree on is the thing that you say that "tadashi did not have to die" is the literal worst take in Big Hero 6. I agree with Grace Randolph's review, it did not feel genuine, it was just tragedy for tragedy's sake.
The way Tadashi went out was too OOC, leaving Hiro near the vicinity of the fire? Mr. Tadashi "I will literally try to bail my brother out of jail even if it lands me in jail" Hamada leaving his brother near the vicinity of the fire to save someone else.
There's no question about Tadashi's hero complex, but the 1st 20 mins showed that his priority was always Hiro then he suddenly leave him near the fire? I would have believed it had he first ascertain Hiro's safety before going inside.
Okay, but using this argument you're still clearly missing the point. HOW Tadashi died is one thing, I often also wish it was handled a bit differently and would've LOVED if his death was more related to protecting Hiro (god, the theories we had before the movie came out...)
But that's still missing the entire point of Tadashi BEING dead serving a purpose. I swear, 9 out of 10 times people only complain about Tadashi being dead in general and not how he died, so my point still stands.
Or just the plain fact that people never think clearly or act "in character" when faced with a crisis out of nowhere (trust me, whatever you think you'd do in Tadashi's situation, you will for a fact NOT do it). Or the fact A LOT of people die in ways we wouldn't expect. If you only care about someone's death if they died "the right way" then I really don't know what to tell you...
And true, Tadashi tried to help Hiro whenever he could, but a lot of people forget Tadashi had a legit life outside of Hiro and Callaghan was part of that life (unlike Hiro who's world was pretty limited to Tadashi and his home life... and maybe bot-fighting if you wanted to stretch it).
In the movie we see Tadashi from Hiro's POV and the series goes a little into this. How even Hiro didn't know "the real Tadashi" because he always tried to be perfect for Hiro's sake. So I'm sorry, but it's totally not beyond me to believe he would "prioritize" Callaghan who's in danger (to his knowledge) over Hiro who was safely outside the building at that point.
Sorry if I sound heated, but that's because I am... Grief is an extremely sensitive topic for me.