you are strangely critical of Ancelotti
would not using the subs allowed to him give him more credit? he's only used more than 3 in 3 matches since the restart and even said he doesn't want 5 subs rule to continue so I dont understand your point at all.
The point is that when you have the opportunity for more substitutes than 3, you also have greater tactical flexibility. You also do not have to think about potential injuries, etc., as you have several substitutes left. This opportunity is quite unique in this period. I do not understand that this can be perceived as being critical.
But yes, he has changed tactics, or at least formation during some matches, and it is good that he is flexible when he sees that the original tactics or formation did not work. At the same time, this can be turned upside down, and say that his plan A was not well enough thought out.