No, it has been like 1 training session and then it has been all games and recovery. Expecting a settled line up when games are coming quickly with little time to recover and players coming back from injury is stupid. At the beginning, Maguire, Yoro, Lindelof, Martinez and Shaw were all injured. It has been all about managing game time and slowly integrating them, and Shaw and Lindelof still got injured again anyway. Overall though, the defense has started to settle, Martinez is our LCB by default, Maguire is center and De ligt is playing on the right. Dalot has started as LWB consistently.
Our defensive set up has gotten stronger, that is a fact. We are giving away fewer shots, and letting teams have less touches in the box than before. We have improved in defense, but we have also got players giving away soft goals from mistakes and stupid decisions, and that is entirely on the players. As for the problem with set pieces, that was there before Amorim as well, and you need time on the training pitch to improve that, which has not been there.
You missed the biggest reason, the players are not as good as you believe. If they were as good as you believe they would not be struggling with confidence, rotation or a new system like some amateurs, the starting line up is also not poor, nor should it affect them in making basic decisions correctly. You are just making excuses for the players for making stupid mistakes.
So, if statistically we have improved in most aspects like having more possession, giving less chances away and creating more opportunities, then that just shows that the system is working. Beyond that is the players responsibility. Blaming the manager when the stats show that your team performed better than the other team and the results were down to the players inability to perform their tasks, is simply ridiculous. Obviously, the results have been shit, but I do not blame the manager for that.
I am confident that things will improve with time. Results usually balance over time with the performance metrics. I would understand the blame if we were being completely outplayed and dominated, but that is not the case. The results are because of the players unexpected mistakes, and seems you are making excuses for them. IIRC, you made a lot of excuses for ETH, when it was obvious that both results and performances were poor.