I think what Pettersson needs is, other than just improving his own play (It's getting there), is a dynamic, skilled, play-driving winger to open up the ice for him and a good aggressive puck retrieval guy on the other side. The lotto line was so good because it had this dynamic to some degree, and the DeBrusk-Pettersson-Boeser line is so bad because it's totally missing it. Boeser is a decent two way jack of all trades finisher that's okay in puck battles and retrieval, but he really just doesn't skate well enough and isn't nearly skilled enough to drive play.
It's odd because we've consistently seen Pettersson be very reliant on chemistry with his wingers and yet the team just totally struggles to either recognize this or land on a consistent model for providing that to him. Sure, in an ideal world you want your franchise C to elevate any winger they play with and to drive play all by themselves like a McDavid or a Crosby, but Pettersson isn't that, and that's fine. He's a supremely skilled, cerebreal 2-way center that relies on similarly skilled and cerebral wingers to, ultimately, put up extremely good numbers and get obscenely good advanced stats. He can be a top 5 C in the league when activated like this, and that's not a weakness for him as a player, it's a necessary consideration management needs to make when constructing the roster.
This is a player that thrived with Kuzmenko and even Goldobin in his rookie year, and neither of those players are nearly as good as a DeBrusk or Boeser, but it's obvious that Pettersson was far better when playing with players like them. Other than just doing the obvious shit with the personnel they already have like playing him with Karlsson/Hoglander/Sherwood/O'Connor, they should REALLY be looking at throwing 13-15m at Rantanen/Marner/etc. or targetting Barzal. After it being a rotting fish market for ages, ur top 6 D is finally solved for the next 5 years: it's time to splurge with the rising cap on a true upper echelon playdriver to unlock Pettersson.