Its driven by performance for sure, but of course its results that triggers my brain to think what went wrong.
I dont like our buildup. With full back inverting that much and so high we put enourmous pressure on our CBs, they can either play to each other safely. Deepest midfielder is usually covered so even if you play perfect ball to him he can be in trouble with opponent on his back. Playing to the side to either FB or winger means they are also under pressure immediately when they receive ball, because they are already up on the pitch, there is no enough width in our own 3rd during that phase. So as opponent you just let our CBs have a ball and press everyone else. Think Bmouth did that very well. We have to play risky passes to progress on our own half. We could sometimes try something different to keep control.
I dont like that our FBs never overlap and always underlaps. We barely send crosses into penalty box. Only those low balls for tap-ins. Arteta was just making his penalty box very crowded, because he knew single full back can cover our winger in wide arena because our FB never plays 1-2 with winger in wide area.
We are bad at both defending and attacking set pieces in my opinion. We lack game management, almost every match our GKs need to produce great saves. Our in-game management if things are not going well is another story... Subs and tactical adjustements against i.e. CP and Bmouth were abysmall (put 2 strikers, but no wingers WHO can cross,.no legs to cover outnumbered midfield) and resulted in being weaker than before adjustements were made. Based on that i doubt Anges sense if Plan A does not work.
How to counter Ange then? Dont press our CBs , sit in mid press and focus on sitting on our deep lying midfielder and fullbacks/wingers. Pack the box and let our wingers have the ball in wide areas if your press is beaten. Dont play too much from the back - since we scored most goals by either counter attacking or when we retrieve ball high on the pitch (i.e. see Brentford match when they played into our hands, or Fulham home last season). Wait for set pieces. Arteta gave exact blueprint this season at our place.