Serie A isn't as competitive as the Premier League, so I think De Bruyne will likely avoid injury during the Serie A season. His skills certainly haven't declined. We saw his performance in the World Cup qualifiers, where KDB performed brilliantly with the Belgian side. The Serie A season is just days away and Napoli first opponent is Sassuolo, a team returning to the top flight. Sassuolo will likely be a tough nut to crack.
We can see KDB there. I hope he can immediately make a contribution to his team in his first match.
I think that the specifics of Serie A are not the main factor that will influence how resistant De Bruyne will be to injuries. The most important thing is that he recovers well from the injury, because Guardiola left him on the bench for a long time precisely because he was not ready to play the entire match, since he was recovering from the injury for a very long time. But a lot of time has passed since then and perhaps he is now ready to play as before without fear for past injuries.