Don’t think it has to do with Buch at all. In 2019-2020 Mika put up 75 points and 41 goals in 57 games.
Buch? Only had 5 more points total than Mika had goals (46 points in 68 games)
Mika’s main issue is settling in and being too comfortable. He just got married and just got a 8.5 x 8 year contract extension. He isn’t skating as hard and seems to play as if he’s just waiting for a powerplay. He makes the right plays, no bad turnovers like Panarin had at the start of the season, and has also been strong defensively, but isn’t trying as hard to create chances. He’s going back to playing like he was before the huge breakout now that he’s comfortable and is seen as a high end player by the team and league wide.
He used to be our hardest worker, someone that would create every single shift, but now looks more like 2015-2017 Mika despite his point totals