Yes, this will slightly disturb the balance of the Napoli striker on the wing. But I think Napoli is a little lucky because the opponent they will face is Genoa. So I think even if Matteo Politano is absent from the match it won't be a big problem. Because actually Matteo Politano sometimes rarely plays in full. Sometimes he is always taken off in the second half around the 60th or 70th minute. But still, Matteo Politano's role is really needed by Napoli when facing quite strong opponents in Serie A. I hope his injury is not serious. And can recover quickly.
Politano is a substitution in Napoli, not their main player and he does not have a solid position in Napoli squad. His injury is unlucky for him and Napoli too as they will not have a quality substitution for a few weeks. Hope he will come back soon but in the mean time, Osimhen and Kravatskhelia as well as Giovani Simeone can cover this absence well. Napoli has very good attacking system and only absence of Osimhen will cause big problems for them.
AC Milan's performance against Inter Milan has never been better in the past. Inter Milan is always a strong team. On the other hand, it was much more difficult for AC Milan to pick up points against Inter. This can be easily understood by looking at the statistics of the head-to-head matches
In the last three seasons, difference between AC Milan and Inter Milan become smaller because AC Milan actually have been in good improvement process. Inter Milan won Scudetto three seasons ago and one season after that AC Milan won it. In the last season, they met each other in Champions League semi final and Inter Milan won but I don't look at these two matches to say Inter Milan are stronger than AC Milan too much.