Be a smart creator.
No one outside of yourself wants to see the 100-page bible you’ve created in order to “fix” the continuity of a character that you love, that you don’t happen to own. No one wants to see it even if you do own the character. Writing it isn’t a waste of time, but showing it is.
The smart creator doesn’t do that. The smart creator does something different.
The smart creator will write a one-shot about a character that they love. That one-shot should be evergreen (meaning it can be used at any time), and it shouldn’t do anything that significantly changes the character.
The reason for the one-shot is to show that you know how to write a comic; the reason its of a character you love is because it shows that you understand the character and the universe they inhabit.
A one-shot is not generic. A Spider-Man story shouldn’t work for a Superman story by just swapping out the names. The care and attention you pay to the character and their travails shouldn’t be stripped away because you’re trying to tell an entire story in twenty-two pages. Instead, your care and attention should be distilled into that story.
The smart creator also creates their own characters and worlds. They can then step back and look at what they’ve wrought, and look to see what is the most viable of their creations. Then they’ll make a limited series out of that, either pitching it to a publisher or self-publishing it.
If it is to be pitched, the pitch document will only show the highlights of the arc. It won’t take the character from inception to one hundred issues down the road, weaving characters and their plots in and out, overwhelming the reader.
So the question you have to ask yourself is this:
Are you a smart creator?