You change the DNA by replacing 4 of the top 4 forwards, and the #1 defenseman.
Because every other component on the team has changed already, most of them multiple times. There's no other original DNA left. The disease can't be hiding anywhere else but there.
Matthews, Marner, Tavares, Nylander, and Rielly. That's the DNA of the team. Has been sine 2018-19. Seven seasons for that group without a single meaningful playoff run. It's a disgrace. And there's no defending it anymore.
So sign anyone you want, it doesn't matter. They've already proven that changes to the supporting cast and goaltending, or deadline pickups and UFA signings don't move the needle. You can't just buy a new trunk lid when the engine doesn't run. The core needs to go. All of them.