pretty good summary.
It's really difficult to establish causality in football, because of the number of variables involved and the fact that everything is changing all the time (form, mood, confidence, the players, the opposition and their strategies).
Agreed, some of these players who left played extremely well under Tuchel, but the last memory is the one that sticks. Heh, I did not think Kai was particularly impressive (aside from his aerial game) today until our players gave up at which point it was just too easy for him and others.
I do think Poch is a bit too much of a yes-man and likely not going to be strong enough to demand the changes the squad needs for next season, so yeah he probably needs to go unless it is to bring a third yes-man in, which wouldn't surprise me one bit.
Maybe next season Lavia, Carney, and Nkunku remain healthy and fit for the entire season, which will help the next manager (and make him look like a genius), or maybe they won't. Or, maybe they are also not all that great -- after all we hardly saw them on the pitch this season.