Did you not watch the Sabres during those years? Mittelstadt was benched and sent to Rochester in 2019 - 20 then he came back and covid shut down the league. Literally in his wiki "Rather than assign him to the AHL, Buffalo management opted to have Mittelstadt play the entire 2018–19 season with the team. He struggled throughout the year, recording just 12 goals and 13 assists for 25 points in 77 games.

After struggling again to start the 2019–20 season, Mittelstadt was assigned to the Rochester Americans, the Sabres' American Hockey League (AHL) affiliate, on December 15"
2020-2021 was a 56 game season he missed 15 games, even if that was injury he still played 3x that, but I know for a fact he was benched some of those games. So you literally have no idea what you're talking about, your just looking at a capfriendly Stat page and making your own hypothesis's

🤣🤣🤣
Whatever you’ve gotta tell yourself dude