Difference of age between Lautaro and Osimhen is very close, but the latter one came as a high-profile transfer in Napoli, meanwhile Lautaro came as a long-term solution so his playing time was very limited in his first season. And you're so wrong about Lautaro not exceling at anything, in fact, Lautaro has better attributes than Osimhen IMO.
Like what kind of different level are you talking about? Osimhen is for sure a great player, but Napoli as a whole is very creative team and they tend to score a bunch of goals in every match. Meanwhile Inter is going through hell atm and we are too limited in attacking phase. Football is a team sport you know... there are many factors to be included when judging a team's run of succees or failure.
Lautaro gets too much hate for not being a Messi in every match. I mean, historically Interisti are pretty harsh and impatient when it comes to delivering. If it was a situation where a player is sucking balls for a long period of time, then okay, but come on, Lautaro has been doing nothing but an amazing job ever since joined and we have to appreciate that.
We are just unfortunate to not have a proper coach, because the core of this team is great.