i doubt if Arsenal was willing to pay that much for Osimhen, they are known to be a team that can’t pay much for players.
Gunners are without a top striker this season, converting Kai Havertz to play in the nine position was good enough for Mikel Arteta but not fully comprehended for the team's pattern of play. Gunners urge to buy more attackers in the frontline. Victor Osimhen would definitely fit into the perfect picture of every elite club, there are passive means of enabling the striker playing for EPL side but Napoli was strictly based on the fee which other parties didn't agree. Arsenal is elite club that are not willing to pay such huge amount for a player, the team's management structure is diverse based on specified amount ought to spend on players.
Arsenal has improved so well to the level that one can be almost sure they will be in the UCL every season. I strongly believe the club has intention to buy a good striker but these days it is not easy to find a prolific striker from one of the top leagues that can fit into Arsenal’s current wage structure. Historically, Arsenal do not like to spend a lot. When Arsene Wenger was manager, Arsenal will not even consider buying Osimhen or any player for that price. Arsene Wenger preferred to develop his youth players. Arteta has his own way of doing things. I believe that at the right time and for the right price Arsenal will sign a striker.