He was a 20 year old talent playing for Lille, scoring 13 league goals in his season for them, then went on to score 10 league goals for Napoli in his first season and 14 in his second. Those numbers are very underwhelming, in my opinion, especially when you consider the level in these leagues compared to Premier League. Even some of his goals this season are a result of bad defending, and while awful defending also happens in Premier League, it is generally much better.
We'd be insane to pay what Napoli are asking, even if we're in need of a striker badly.
He is insane aerially, though, and he's become much better in that aspect, but even his own manager said he expects more from Osimhen and that he needs to learn to work with his team mates. I really like him, but we shouldn't pay €150m for someone who relies that much on service from his team mates.