He's generally good when he doesn't need to create his own time and space and isn't under pressure. That's why he's generally good on the PP and in OT when those situations are baked in. And when he's at even strength where you don't get as many of those situations is when he struggles most with turnovers, losing puck battles, etc. Most of the game is played at even strength. Most of his good plays and points are generated on the PP, or from playing with other guys (Kaprizov) who can do the hard stuff, all Zuccarello has to do is touch the puck at some point.