Back on the ETH topic, it was obvious he needed time to implement the system he wanted us to play in, but what surprises me is his adaptive and motivational capabilities. He learns from any mistakes very quickly and makes sure that they are eliminated as soon as possible.
In the Man City game, he realized that the team were still in a "holiday" zone with their movement, especially the midfield lacking control and he immediately forced a change with Casemiro replacing McTominay in the next game, despite McTominay having a successful four to five games prior to the Man City game. Even in victories, he will change players who don't seem to be contributing such as the Sancho case. He has created a disciplined, team-based attitude where everyone is driven to win.
In terms of tactics, ETH is quite flexible. The game might start with a 4-3-3 or a 4-1-2-2-1 but depending on where the opponent is weak and strong, the midfield shape changes accordingly. The key positions are the 2 midfielders on either side of the DM which is either Fred, Bruno or Eriksen. They act like free-roaming central midfielders, where they take up positions to make the line between the defense and attack compact. During attack, they can play the role of AMs, false nine or inverted wingers depending on the current positions of the attackers and during defence, they typically form a 3-man defensive midfield to narrow down the opponent's passing channels. It is a very fluid midfield shape which influences our attacking and defensive movement.
It would be interesting to see ETH's tactics against managers like Ancelotti or Mourinho, who are excellent at studying their opponent's formation shape and creating a counter formation. Even if ETH gets a bad result, he will learn immediately and will not repeat the same mistake against such managers.