I didn't elaborate earlier because the humidity and other arbitrary stuff are making me super depressed and I did not have the energy, but this is exactly it.
There was some of this in the first Avengers movie, but you're right, MCU really dropped the ball on superheroes saving people.
Like, I remember, a few years back some rando on tumblr said something about super heroes being a fascist genre because their purpose is to collaborate with and enforce the power of the State, and this argument makes sense to make about the MCU.
But it's not what superheroes are about.
There's a lot of things superheroes could be, but one of the most important things is a vision of "What if there was a person with power to help people and that person was GOOD?"
And "using powers to help people" doesn't mean "collaborating with the government" or "fighting crime in collaboration with the cops" or even "vigilante justice" even though all of those things have come up a lot in superhero stories to the point that people can have a hard time thinking of alternatives
But there are plenty of alternatives. Saving people from natural disasters/accidents? Taking care of and protecting people the system doesn't help? Protecting civilians in a warzone? Shielding people at protests? Oops, now your superhero is considered a " terrorist... "
That's the thing, a superhero advancing the cause of good would have a hard time not getting into conflict with the government. A superpowered individual that collaborates extensively with the State might not even be a superhero. There's another archetype we could look at, that of the supersoldier. A superpowered person who is either created by a government's military or appropriated by it to advance the goals of the State.
Supersoldiers and superheroes are pretty different, and in some ways, non-overlapping things, and MCU ended up conflating the two.
I feel like any kind of satisfying arc for Captain America would have had him STOP being a supersoldier and start being a superhero, and of course MCU shat the bed on that one.
Once again, Captain America: The Winter Soldier was the best MCU movie, showing Cap's depression and then existential crisis as he realizes the government he was working for is evil and corrupt, and as with every other aspect of that movie that made it so great, the creators were like "UH OH" and never did it again.