Introducing Wirtz as a 10 has been a massive game changer. We effectively committed to 4 up front doing that, leaving us very weak in the midfield 2. A genuine 6 might help that, and I would look to that personally, but I think Slot has opted for (based on tools available to him) to get all of the front 4 working harder defensively, which more and more they are now.
Wirtz is stronger and fitter, Hugo is fitter and has been told to work more. Salah has clearly been told and accepted the same, and now we're seeing improvments all over.
Konate and Virg are then only having to win one on one duels, rather than being overrun and swallowed up. Meanwhile Kirkez is getting better each game, and we're getting away with it at right back, since Dom and others are doing well there.
It's definitely improving, Slot just needs to keep his mouth shut in press conferences and play more of the bench to help protect health of the main players.