The issue with Brandt is that he has the gift of being able to ruin his team's momentum entirely by himself. He wants/needs to be the most centralized played of his team and that just doesn't work with a player, who is a bit sloppy on a good day and a turnover machine on a bad day. Because every time he loses the ball in the middle of the pitch it's a prime pressing/counter attacking situation for the opposition, you can see and feel how they devastate his team's morale and confidence.
Meunier's turnovers are different, because he's playing on the outside of the pitch, if he overhits a pass it's annoying, but his team is usually still in an okay shape and they can mostly just go into an organized pressing, or it even results in a throw in. It's also not like he's seen as a key player.
Dahoud didn't play well last season either, but he was fairly reliable in Terzic's first season. He also less reckless against pressing opponents.
Bellingham is actually a relatively reliable passer. He usually produces turnovers via dribblings, which he does where they are supposed to happen, in reasonable attacking positions where his team expects them and where's a real upside to them. He's also fecking 19 years old, while Brandt is in his prime years.
Emre Can is in the same position as Brandt, he isn't supposed to be a starter and the club would like to get rid.
Hummels is getting old and he has his flaws, but I don't see how anyone would compare him to the calamity that is Julian Brandt. If Sülinho and Schlotterbeck perform as well as people hope he'll also struggle to get a starting position.
And unlike Brandt all of these players actually put in the work against the ball.
I don't know how high you rate Rose, but I would like to phrase it a bit harder: maybe it is the lack of a real possession/attacking system that lead to players taking too high risks.
And yes, that is a general pattern with coaches who like to focus on transition and counter attacks. Very few master the art of truly coaching and training attacking moves that can be executed reliably.
The problem for Rose was that the squad was/is still heavily shaped by the possession ideas of Tuchel, Bosz and Favre, while the club wants to switch to a more direct style. Which means it's not set up towards one cohesive idea, which means endless painful compromises for the coach, e.g. trying to play a direct game, but then having super slow players like Witsel and Hummels for cover. Trying to play a pressing game, but then having players like Guerreiro and Brandt in the team.