It seems that in the next season Napoli not only wants to chase the Scudetto, but it seems that Napoli wants a more prestigious trophy like the UCL trophy. Because in my opinion Napoli really has to increase their desire a little more, so that they can continue to develop and remain stable as a team that can compete tightly in Serie A. Because currently Napoli is no longer a team that is underestimated, because last season Napoli managed to become champions in Serie A. This proves that Napoli's quality is now different from before. Therefore, I strongly agree if Napoli fights very hard in the transfer market this time to improve their team to be even better.
They can want to defend the Scudetto and also perform well in UEFA Champions League but this ambitious target for a next season will result in a lot of pressure on Conte and Napoli players. It's not easy for a club with limited player resource like Napoli to play well in Serie A and Champions League while I guess their main target is defending Scudetto that itself is not easy already.
By playing in Champions League and also aiming for good performances there, Napoli will be affected a lot on their performances in Serie A. With limited player resource, they will struggle to diversify their players for both competitions and in a long season, it contains high risk of exhaustion and dramatical decline in player fitness and performances. If Conte and Napoli won't prepare for it well enough since this summer and won't manage a next season carefully, they might have a very terrible season.
I agree with your assumption, because it is true that it will certainly be quite difficult for a team like Napoli to be able to perform well in two competitions at once. Because of course Napoli players are also ordinary people who definitely need a long recovery period after each match. Even elite teams like Barcelona and Real Madrid sometimes find it very difficult to perform well in their domestic league and also in the UCL at the same time. So with that, Napoli certainly has a journey that will certainly be quite difficult next season. Because as I said, Napoli definitely wants to chase the UCL trophy and it seems like they also want to defend their Scudetto title. So in my opinion, if Napoli wants to perform well in the two competitions, the solution is that Napoli must be able to develop all the existing players, including the second-string players, very well. So if possible, make the second-string players like the main players. If Napoli can do that, I am very sure that Napoli will perform optimally in the two competitions.