The Italian championship will certainly be much more difficult than the one he played in. In England the defences are really embarrassing, and it's normal that he scores all these goals. Now we'll have to see if it will be like this when he plays in Italy. I'm convinced that if he gets going he'll score a lot of goals.
KDB's focus in playing is as a playmaker to support a good attacking flow for movement and supply to the strikers in the attacking line, and scoring goals is just a bonus for him, so he doesn't care how many goals he scores as long as there is good supply to the attacking line and he can pass the ball smoothly when building up attacks from midfield to the front, which is already very good for KDB because that is his role.
Scoring goals is not the main focus for a midfield player, but creating space through well-timed passes. Especially since KDB is already very skilled at direct passes, which can bring a slightly different flow to the quality of the attack in the end. I believe that even with the current conditions, despite a slight decline, he is still capable of doing that in Serie A. However, it does depend on how he adapts to his new club, as the slightly slower pace should not pose too much of a challenge for KDB in terms of stamina, even though he is over 30 years old.