Thanks for a very reasonable post.
My views on our side of the game last night.
4-4-2 appears to be the formation that best suits us. It kept Man City at bay in the first half (I'll comment on your goal lower down).
You don't take your best player off (Davies) and leave Siggy on.
Man City's first goal: no way that was going to be a goal - Pickford was down and covering the trajectory of it, and then came a big deflection. A VERY lucky goal indeed.
The second goal: ANY Manager worth his salt would be telling his players to show Mahrez his right-side (i.e. do not under ANY circumstances let him cut inside onto his strongest foot). Same as with Salah (on Saturday). At the edge of the area get tight and do not let him come inside. Basic. Even without any advice of the Manager, players know the strengths of opponents, particularly attackers. A totally self-inflicted second goal.
The third goal: If we have a goalkeeping coach, he should be drilling it into all of the keepers that when you dive for a ball, you go for it with TWO outstretched arms. Go for it with one, and there's a very good chance that there will not be sufficient strength/force to prevent the ball going on behind the keeper. Again, this is basic. There is really no excuse for that third goal. Basic goalkeeping error.
Although City had far more possession (which was to be expected) the scoreline ultimately flattered them. A fluky first and a basic goalkeeping error...