Hansi Flick fucked it big time imo.
Firstly he overused our starting players in games already confortably won even by HT and kept playing them absolutely for no reason instead rotating/resting them and give chances to the likes of Victor, Fort, Martin even Ferran particularly when he knew all to well he doesn't have quality subs for them.
Thus the starters got more and more fatigued and injury risking. The result was Lewa, Balde and Kounde all got injured in the most critical part of the season and he had to start playing the players he didn't sub even when winning confortably in LL vs. the fecking Inter in the fecking SF of CL out of them all.
Secondly, he didn't manage to make Barca able to defend Inter who is not a great attacking side by any means. Inter scored in two leggs whenever they needed it. I thought Flick learned his lesson and that the return leg won't start AGAIN from 2-0 for Inter but guess what, that's exactly what happend in both matches. Inter scored 7 goals out of 10 shots on target, that's completely unacceptable.
He also started Olmo at Milano instead of starting Fermin who could run and press more and bring Olmo when Inter was starting to get tired.
He persisted with Martin too.
Ofc individual blunders weren't on him but still, he is the first to blame for what eventually happend to the team in CL desipite individual errors.