It's like there has been a pattern for them about manager choices. Vitor Pereira, Jorge Jesus and Mourinho all have been followed by İsmail Kartal so far. I think it's better to have a Turkish manager if you want to win the league. Because he'll know the environment better than anyone.
With this squad, aiming only for the domestic league title seems pointless to me. If you also look at the European matches, success in Europe should definitely be the priority. Fenerbahçe must at least reach the quarter-finals, or go even further, in the UEFA Europa League. So I believe a foreign coach is absolutely necessary. If their only target is the domestic league title, then they can continue with a local coach like İsmail Kartal. But in that case, all the money they’ve spent would end up being wasted in my opinion.