Here's my Nylander take, and I've said it before. Willy can be frustrating to watch for sure but while it looks like lack of effort that's not what I see. Contrary to what seems to be a perception of him being uber confident, even arrogant, I see a player who struggles mightily with confidence. When he's "lazy" it's not effort level it's confidence, he's unsure, hesitant, afraid to make mistakes and is paralyzed by that disbelief in himself.
Playing with Tavares just exacerbates the issue. Not only do their styles not mesh, but over the last 2 years the chances and goals against have just piled up when they're on the ice together to the point that as soon as they step on the ice together Willy 'knows' it's going to go poorly - so it does.
You can argue he needs to fight through that mentality but it's like telling someone who's depressed to 'cheer up'. If only it were that easy.