Okay, but see: as I understand it DID pretty much universally develops during childhood. So in order to reflect the reality of the disorder I'm not sure that would work.
I'm pretty sure people with DID don't "decide" to have distinct identities (they're also not referred to as "identities" irl either). Framing it like this would probably be seen as an extremely disrespectful and potentially harmful depiction.
That is a bit besides the point though in the sense of that being the way the story is told in the comics. In so much as they are going to draw inspiration for this property from the books. I don't think it's a good idea, radically removing aspects that make the character stand apart from his peers like Daredevil or Batman. Though obviously they could.
Also, I think you are misconstruing what I meant by "decides".
Spector doesn't make a conscious decision per se to develop dissociative identity disorder. He intentionally creates cover identities, at the start no different than Batman's Matches Malone identity or Crocket and Tubbs' undercover IDs. Again, somewhere, somehow along the way the lines began to blur for him and the Grant, Locksly and to an extent Moon Knight itself becomes distinct from the persona of Marc Spector. Which again, doesn't point to Khonshu as "making Marc unstable" in some direct sense. A spell wasn't cast or some soul tampering or whatever comic book concept one can imagine. Classically what develops in Marc is indeed in Marc's mind as a result of his life experiences, which, if you want to go into childhood, I mentioned the father/son relationship, which is a drama all it's own based in Marc's father's rabbinical piety as well as Marc's youthful shame at what he thought of as his father's weakness and how this swirled to make the younger Spector fashion himself into all the things he sees as the opposite of the supposed weakness in his father. A clash with a Nazi who was living as a Rabbi under an assumed Jewish identity in the Chicago community that Spector and his father lived in, where the man nearly kills Marc, is often cited as a big inciting incident for his DID.
Which... Young guy is clashing with his father with questions of masculinity and acceptance into the wider American society jutting up against the trauma of almost being killed by a Nazi, who disguised himself as a Rabbi to escape justice?
I'd say that would fit your bill for an event in one's youth.
Again... I'm not laying out anything that's not in the comics and the specifics of your objections don't apply as neatly as you assume they do I think.