I think a situation like Chicago might be good for him. Massive ice time, ride shotgun to a star, no pressure re playoffs for now, and they can afford to pay him a bundle.
Marner's ideal environment is probably Florida before they got good, and he can have an easy time being a super productive regular season star like Huberdeau far from the limelight, only intermittently in the playoffs, making the big bucks. This allows him to continue to be who he is, excel at what he excels at, at the price point he's used to.
The alternative is he accepts a Phil Kessel like role on a team ready to win, but in order to follow that path he needs to be making less than $9 million and move out of the Panarin, Pastrnak salary bracket. Stop being delusional about being a franchise cornerstone who can deliver a championship.
Marner is at a crossroads in his career, and staying in Toronto continuing to do the same thing is not the right answer.