TBH so far the only game I truly think it was on him tactical-wise was Udinese.
I watched the whole game after, after the first goal up till 30 mins basically the first 2 subs, it was a tactical error, and he also didn't coach them well enough before game to playout from the back like that. After that he put some targets up front for long ball, hence creating back the space at the back a bit, but the defense set up was still horrible, and the reasons we weren't losing till
de Vrij came in was Acerbi surprisingly played well, and we got a bit lucky.
In short that game he got outcoached in so many levels, but again Udinese had a great start this season so far, and I would contribute it mainly to Sottil (Reminds me a bit of Josh Brolin).
In terms of "losing the locker room", I would say it is the Mercato, and Sunning and management wrongdoing mostly, but of course a spectacular coach can keep the team spirit floating in these extreme circumstances, that one could argue, but this one is quite not the typical crisis thing, it is more of club is treating you a saleable object than the club is broke, like you can't motivate the player when your boss is yelling they don't value the player (or they value some money more), and want to get rid of them.
At this point I am not even sure if getting a new coach can motivate the team, maybe? cause grass is greener on the other side, at least we should have some honeymoon period, but it won't fix the underlying problems.