I also buy the Tuchel needs time argument to an extent, but some of these players, and how he's setting up is relatively similar to what we've seen before. I hark back to the Denny Green They are what we thought they were comments. At some point, three guys, no matter how talented, who have no desire to come back and defend or get involved in the scheme are going to struggle when they play a side who might be a bit less talented, but is committed to put in a challenge and work. The gap isn't that far between Liverpool and PSG to where if PSG doesn't put in a full effort, they're going to struggle. Neymar isn't paid to play defense, track back, or what have you. But his contributions in that arena were laughable. He at least has to give an honest effort in that area.
I also have some concerns on whether or not the players he has will be willing to do what he's comfortable with. He's a good coach, but I'm very interested to watch how well he can manage and get his players who don't want to track back or commit to do so.