If there's one set of words I would never expect to see next to Mitch Marner, it's "effort level was atrocious". Even when he's not producing, Marner is still TRYING... Now, you can argue that his trying is counterproductive, but not trying?
OTOH, I still see periods where it looks a whole lot like William Nylander just doesn't care about anything but scoring. And yeah, his annoying tendency to react to losing the puck by going for a change is starting to grate. Reminds me of Game 6 of the second series against Boston a few years ago...