Osimhen and Icardi are great duo, but I bet that we are going to see plenty of games where one of them will miss, could be resting, could be injuries, could be anything really. So they are not going to play with two strikers in every game, and Icardi doesn't need to be always ahead, we have seen him plenty of times to fall back on midfield to distract the defense and pass the ball and playmake too, so I am guessing he is going to be more of a shadow striker, and let Osimhen be forward.
What is interesting about the players is that they can both replace each other which is good in case of injuries, although Victor is not always prone to injuries. Icardi is a good player but the presence of Victor Osimhen will bring out the best in him and make it more competitive. I see Galatasaray winning the Super league title this season, although we have not seen what other clubs and bringing on board for the new season.
That would be the main reason why they have two right now, every team has a "bench" player for almost every position. The real trouble however is that neither of them can be benched, which means, while in some games they are going to be alone, like not both together out, in many of the games they will both be out there.
And playing with two strikers is not an easy decision, that means you are going to have to give up on something. In this case, they are planning on not having 2 wingers and 2 backs, instead have 2 wing backs, and instead of 2 centre backs, have 3 centre backs. This way they drop 1 player from there, and make the wings run a lot more, help the defense while also be there for offense, this will make it very hard for the wing backs without a doubt.