Joker, in a way, is the hero. Because of his popularity as a villain, most comics and movies with him in it is going to make a lot of money, wether it’s good or not.

As a self-aware character who is constantly breaking the fourth wall, it’s possible that Joker’s trying to bring attention to whatever media he’s in.

After all, the Joker has super-sanity.

I’ve never read anything where Joker breaks the fourth wall.

And breaking the fourth wall is not automatically the equivalence of cosmic awareness. Black Hand introduces himself and his backstory directly to the reader in his first appearance. Etrigan thanks all the writers and artists who have given him life in the final issue of The Demon Vol 3. Lobo constantly cracked meta remarks specifically for the reader.

These are just writing techniques, not character abilities. Ambush Bug is one of the few characters you could argue has cosmic awareness, but it can be equally debated that he his just a slapstick character and breaking the fourth wall is still just a comedic trope, not an actual power set.

“Super sanity” is an overhyped buzzword used by Jokerised fans in the way “prep time” is flung about by Bat-God worshipers as if it renders any contradicting argument moot.

Fries stopped dedicating his life to his wife long ago and became consumed by bitterness. He doesn’t just subdue people who get in his way, he inflicts as much pain on his victims as possible. He wants people to suffer as he feels he suffers.

Joker’s not even technically breaking the fourth wall there. It’s just a lunatic talking to himself in a cell.

It’s not even close to Ambush Bug self editing the story as he goes, Etrigan mentioning Kirby by name or Lobo doing instructional tutorials and pulling a reader into the comic itself.

Well joker said "has it ever occurred to you doc,that we are fragments of theirs?" After the doctor says that his imaginary friends are fragments of his imagination, and he calls them his "fans",that looks like breaking the fourth wall to me.

Here, Joker literally tears through the comic page.

So if someone said that to you in the real world it would make you question whether you were a fictional character or not?

It’s written with intentional ambiguity. It incorporates two contexts. In universe, Joker is simply talking to a doctor, raving about a delusion that he has fans cheering him on. Out of universe, the reader gets the inside joke that Joker’s insanity makes sense to us.

I actually went to know what a joker-burger taste like.