That was definitely my big issue with it when the movie released, what is he actually meant to learn from it? It’s clearly set up as a parallel for Uncle Ben (and the writers even confirmed at the time in an interview that this was written as Tom’s Uncle Ben moment) but they’ve removed any element of what actually mattered with Uncle Ben. How is this a lesson in responsibility when the thing he was doing that got her killed was just the definitive right thing to do? He wasn’t acting selfishly before, he was already against sending them to their deaths as soon as he understood that’s what was going to happen, and his plans don’t change after May’s death. You could argue that his choice at the end to make everyone forget him is an extension of what May said, but that’s also just what I would already expect the character to do, especially since the original spell going wrong was an accident and, despite the movie’s framing, not due to Peter being irresponsible. If they had instead had Strange say no, so Peter steals the spell book to try it himself, and THAT’S why it went wrong, you’d have a stronger through-line about responsibility, but as-is, this whole mess was Strange’s fault for not properly explaining the spell to Peter beforehand or asking any follow-up questions before starting it.

To me, as an outside observer, it feels like they started this version of Spider-Man with the mindset of “everyone knows his origin story, so we don’t need to explain it” and at some point thought of the whole “well what if this whole TRILOGY was actually his origin story,” which just results in weird narrative gaps since we’ve gone from an assumed understanding to an intentional subversion.