Personally, if I had to book Punk’s return, I’d book him as a monster heel going after Triple H. He’d cut promos blaming Hunter’s ego for running him out of the company ten years ago, and he knows that Hunter only offered him a contract because he knows it’s “best for business”, but he doesn’t care about business - he wants revenge. One by one, he goes after all of Hunter’s golden boys and beats them. Austin Theory, Dragon Lee, Kevin Owens, one by one he beats them all. He even goes down to NXT and wipes the floor with Bron Breakker, Cameron Grimes, and Ilja Dragunov, and wins the NXT title, but he refuses to accept it and just tosses it in the garbage on his way out of the arena.
Eventually he enters the Royal Rumble and wins, but refuses to pick an opponent for Wrestlemania. He explains that the Rumble ten years ago was his last match in WWE, and he had it won, but Hunter didn’t think it was “best for business” back then and so had Kane eliminate him. Back then, the only thing he wanted, the one thing he’d never achieved, was challenging for the world title in the main event of Wrestlemania, but he doesn’t care about that anymore - he wants a match with Hunter instead. Hunter, of course, says he can’t wrestle because he’s retired, and books Punk against Roman and says Punk is fired if he no-shows - and he assigns Shawn Michaels as enforcer to make sure the match goes as planned.
Eventually the main event of Wrestlemania rolls around. Punk and Roman get in the ring and square off… and Punk immediately lies down on the mat, refuses to move, and yells at Roman to cover him, and Roman, disgusted, obliges and pins him before HBK can intervene. The crowd starts booing the hell out of the place, and Shawn gets in Punk’s face and starts yelling at him. Punk snaps and starts beating the hell out of Shawn, then gets a chair and threatens to cripple him unless Hunter gets his ass out there right now - and Hunter makes his way down to the ring, pulling his tie and suit jacket off as he goes, and gets in the ring, and they have their match, which Punk wins before riding off into the sunset never to be seen again.
But what do I know? I’m just a mark.