Superhero universes are, once more everybody, gestalt creations combining in a linked fantasy narrative a myriad of genres. Thus whether DC or Marvel you can have on their all star teams characters whose origins are drawn from all over fantasy, up to and including genres that may well seem antithetical to one another.
The alien from another world, the mythological god/goddess brought to life, the swashbuckling "human" hero in the peak of mind and body, the character empowered through some "scientific" accident, the person born with some ability drawn from a quirk in their genetic code, the powerful sorceress or wizard, the hero who is a product of some sort of experiment or one enhanced by cybernetic technology, the fantasy based genius character that can create weapons and other devices that go beyond any known real world technology... It's all a go. All of it exists side by side and has done so for 8 decades.
There is honestly zero reason to have to have a unified field theory of super heroes for the big two purveyors of spandex clad champions. Some creations obviously aping DC/Marvel characters and settings find that "one explanation for all fantasy/ sci fi elements" in the narrative to be a useful aspect in the storytelling. But most of those are acting as commentary on the Marvel and DC characters and universes. The others are just outright attempting to copy the all things fictional/fantasy are a go approach of the big two.
Because ultimately I think no one but the most persnikety and ssomewhat oblivious fans of the big two are at all asking for the all consuming rationale to hang their suspension of disbelief upon. Yes, there is no denying that even fantasy needs some rules and structure and in universe rationales to stop things from spiraling into a chaotic mess or devolving into some rule free stream of consciousness nonsense. That's not what any super hero fan is looking for... At the same time among both the dedicated fanbase and now the general audience there is this misunderstanding by some fans thinking the rest of the consumers absolutely need some air tight rationale or that somehow it's a complete narrative failure if not every single detail can be expounded upon with the absolute precision required of say, a book about math, technology or science in general.
The answer is always in my mind... It really doesn't. It didn't need it before in the previous 80 years and it's not necessary going forward for the next 80 years.