I would also point out that many characters in the MCU feel guilt for things they’re not entirely responsible for, or where there was no good solution, in addition to the things they actually have screwed up. This is so common that something like half the Avengers have issues with it, and how they deal with those emotions is a major running theme of their respective stories. (And yet, this is often considered the light-hearted superhero franchise compared to DC.)
Iron Man has a real guilt complex over Ultron, even though he actually wasn’t responsible for it. He never intended to create Ultron, at least not at that time or in that way. After Wanda messed with his mind - and we see how that affected everyone else - he was still only investigating the Mind stone, which activated Ultron more or less on its own. He’s neither the first nor the last to be caught off-guard by an Infinity stone, moreso because the Avengers still don’t seem to know what they have their, possibly excepting Thor. This doesn’t help him escape that feeling, though, and Stark is trying to step forward and actually be mature for once. Interestingly, the overall Marvel series seems to imply (to me, anyway), that his father followed a similar path. Young Howard Stark was brash, idealistic, excitable, and constantly rushing about doing his own thing. But we that later in life, he was very serious and emotionally reserved, with a strong sense of duty partly stemming from his failure to prevent problems.
Or here’s another one: In Civil War, Wanda has a problem with how her actions destroyed many innocent lives during Crossbones’ attack. The fact that it simply was a bad situation, and possibly nobody could have prevented some casualties, simply isn’t going to make her feel any better or fix the problem. In part, we see that she wants to prove that she’s on the right side, no matter the personal cost.
I’m not saying this is the only way to look at characters, but it’s such an important theme that you can look at, and understand, almost every hero in that light. Cap? He survived everything, even death, and he isn’t going to fail to save Bucky a third time. Let’s not even start with Black Widow, whose uncomfortable history just drips with… red. Or even some of the villains. Loki and Zemo, for example, are characters driven by a deep sense of inner shame they can’t escape.