There's a scene in one of the early issues of Gwenpool, where she explains the truth of his existence as a comic character to Batroc. When Batroc questions why he has never experienced his happy moment, his great triumph, Gwen points out that he's the villain. He's not meant to experience success, but he doesn't realize that. He goes into fights with Captain America or Misty Knight, and thinks that maybe this time he can win. From Gwen's perspective, there are outside forces that have put certain rules and conventions in place which dictate Batroc's actions and fate, which he doesn't perceive.
Gwen, because she thinks of it all as a fictional universe, doesn't operate that way. She knows what the conventions are, and so treats it like a minefield she has the map for. It was in the Rocket Raccoon and Groot book, but there was a bit, once Civil War II started to intrude, where Gwen forcefully states she is not going to New York with Rocket and Groot because minor characters get killed in Big Crossovers, and she knew she wasn't a big enough deal to be safe. It was entirely possible that if she went with them, the Guardians spaceship might have landed on her. She wasn't going to play Arcade's dungeon by his rules, because she saw the larger pattern of what he wanted, and didn't see any reason to play along. Why fight these other mercenaries who aren't doing anything to her? Just find a way out, trounce Arcade, who is the one actually trying to kill them, and get on with your life.
She did make the mistake of buying into her own hype and thinking she'd be able to kill Deadpool, when, as Wade pointed out, there is no way she's popular enough to get that carrot. But she doesn't like Deadpool, and her plan to take him down through teamwork had worked spectacularly well, so you can't blame her for getting a little cocky. It happens to the best of 'em, and for the most part, she's avoided being jerked into pointless scuffles and dangerous situations.
But then there's Deadpool. Wade knows he's a fictional character, but unlike Gwen, he plays by the conventions of his universe. Normally he limits his awareness to commenting on the stupidity of events, or the convenient happenstances that keep certain plots moving. Wade knows all about two heroes having a misunderstanding fight, then teaming up, but he embraces it, looks forward to it. He knows Arcade is trying to make people kill each other for him, and Deadpool pretty much shrugs, says, "Sure, why not?" and gets to be stabbing. Wade explained it to Gwen as 'We all just live here, right?' Deadpool knows there are strings on him, but much of the time, he doesn't seem to mind. But sometimes he does. The second story in the final issue of the previous Deadpool volume (either #45 or #250), he gets the Infinity Gauntlet and has a roast in his honor. At the very end, he talks directly to us about how much it sucks sometimes that all the misery in his life is for our amusement, and that we treat it at disposable entertainment, but it's real for him.
That, combined with what he told Gwen, makes me wonder how much Deadpool uses what he knows about his existence as an excuse. Wade is capable of compassion, but generally demonstrates it towards people he regards as innocent victims. Agent Preston, his daughter, Ratbag from Simone's run, Weasel when he's gotten in trouble for helping Wade. When it comes to people he regards as having made bad decisions of their own accord, he's indifferent. He was supposed to be protecting Michael from having his soul claimed by Vetis, so Wade shot him in the head to send him to Hell as a way to outflank the demon. That it sent Michael to Hell didn't bother Wade much, seeing as Michael was the one who made the deal.
I've tended to attribute this to Wade's traumatic experiences at the hands of Department K, the people who experimented on and tortured him in the process of giving him his healing factor. Wade didn't know what he was getting into, he was a victim, and so he feels sympathy for those he sees as being in similar straits. Because the world has been so cruel to him, he can therefore justify being cruel back. No one was there for him when he was in trouble, and even now, years after, even having saved the world a couple times, a lot of people, including heroes who ought to understand what he's experiencing, still treat Wade like something they'd rather scrape off their shoe. Deadpool struggles against those impulses, frequently tries to be good, tries to help people, builds connections with others, but he often fails, and ultimately it all goes to hell.
But if Deadpool knows his life is a story others read for amusement, that it's being crafted by other beings in whatever ways they deem fit, how does that impact what he's doing? Deadpool goes through a lot of supporting casts. There are certain characters who will carry over - Weasel, Sandi and Outlaw, Taskmaster pops up a lot - but most new writers want to introduce their own set-up (when was the last time Blind Al was a major part of his book? Early 2000s?). Wade goes from having a small, but solid core of friends who will come have a TV night at his decent apartment in the final issue of Cable/Deadpool, to living alone in a warehouse at the start of Daniel Way's Deadpool. What did Wade do to screw everything up that fast? Did he sabotage friendships because he knew he was supposed to be isolated for the new run, or did he choose to isolate himself so he couldn't destroy his friendships, so he could hang out with his friends again somewhere down the line?
Does he jump at the chance for the misunderstanding battle because he knows it does lead to a team-up, so he'll get to hang out with Spider-Man or the Thing? He could try talking to them, but that might not work. They might see Deadpool and just hurry away. At least this way they'll hang out with him. He does get lonely, he would like for these heroes to like him at least a little, though he's often unwilling to show the more decent parts of himself to them.
Does he kill nameless cannon fodder because he knows they were put there by the writers for that purpose, that nobody cares whether they live or die? If so, is it because it makes it easier for him, or because he's trying to put on a show for the audience, or maybe he even thinks he's doing them a favor. The nameless HYDRA guys he and Preston killed in issue 24 were put in the story for that purpose. To die in a manner that shows how serious the protagonists were about all this. They were created to suffer, and he's sparing them any delusions otherwise. It wasn't all strictly necessary; some of the HYDRA guys surrendered, but Gerry Duggan was trying to be dramatic, so they were coldly murdered anyway.
Wade in 2099 told his daughters and Preston he never asked for any of them, to have this weird family full of people who all kind of hate him now. For most of us, we'd interpret that as life moving in unexpected ways, if I hadn't been late for that train, blahdeblah. Wade knows it wasn't random, it was written in that he'd take that job from Dracula, meet Shiklah, marry her to keep her free of Drac, and they'd have a kid. From his perspective, does he see it as something he had any choice in whatsoever?
Thinking about it, even Wade's memory problems, which are usually attributed to either the constant regeneration of his brain, or more recently, the drugs Butler was giving him, could be instead laid at the feet of the creative teams who add new stuff into his backstory. Butler wasn't part of Deadpool's history, until he was. Or T-Ray, or the idea that Wade went into the future and saved Young Cable's life multiple times, so that Cable knew Wade before they fought the first time back in New Mutants #98. The Deadpool who appeared in that New Mutants comic probably didn't even have memory problems, because nobody had bothered to write that into his character yet. His mind might have been reasonably sound (by Deadpool's standards), but has gotten progressively more wrecked over the years as writers put him through the wringer, adding new layers to his history, fixing the memory issues one way, adding them a different way later. And Deadpool, unlike Wolverine, knows he's never going to get that moment where he remembers everything. Because even if he thinks he does (ala Logan post-House of M), some other writer will come along with some other thing out of his past he didn't recall for some reason.
What does that do, if you know at any moment someone is going to come along that 5 minutes ago, you had never heard of, but now it turns out they were super-important to you in the past, you had just conveniently forgotten until right then? It's happened before, it will happen again. Would you still be able to be surprised after awhile? Would you still be able to care? "Yeah, I know we were best friends in 7th grade and I stayed at your house when things got ugly at home, but you didn't exist until three pages ago so piss off."
I started this with the idea that Deadpool used what he knows about his existence as an excuse, and it might still be. When things start to go south for him, if he backslides more towards being a bad guy at some point, he might claim it's what Marvel thinks is most profitable, not his fault he's ruining everything. But looking at it, all the jokes and jabs about pointless fights or losing his co-star to a better-selling X-book feel like Deadpool taking the one bit of solace he can in the shitty hand he's been dealt. He doesn't see anyway to get free of the strings. He won't be allowed to step off-stage until Marvel decides he's not popular enough to keep alive. So he shittalks them because it's the only little way he sees to get some back at them.