The Movie DC universe and the comic book universe are not one and the same.
Obviously you will need visuals, so concentrating on the movie and TV universe would make more sense for you.
Batman was a serial back in 1943,
https://www.youtube.com/results?search_query=batman+serial+
Superman was in a series of cartoons from 1941.
https://www.youtube.com/watch?v=NZag6pDDWbc&list=PLYuTxcgUHuU2HleIBzGQpIR2L-i6rfeGD&index=2 Both were on Radio well before then. There is enough material to keep you going for a long time.
Thing is tho, the kind of thing you say you want to do - for money obviously - is already being done - Comic books, TV movies, animation about TV, DC or Marvel, is already being done. T there are 100s, if not thousands of channels on YouTube, not to mention blogs, doing exactly the same thing.
If you want to find out more about DC, have you ever heard of Wikipedia?
It's all out there if you are willing to take the time.
It bothers me that you say you are a Marvel fan but know absolutely nothing about DC. You are clearly not a comic fan as that is so unlikely as to be impossible for a real comic fan.
Good luck for you on your money-making venture. However, most of the people who run Comic or Movie based You-Tube channels have more than a superficial knowledge of the subject matter and when you visit one who doesn't, you move on!
But at least, you yourself, might increase your own knowledge bank.