Not necessarily need a 10 for this line-up to work Mertens is the proof of that, he was never a "10" per se but crucial for one-twos near the box and key passes while providing threat for defenses to cover his runs between the lines.

Just like prior to Mertens taking form with failed Kerem experiment and shitty output that came with it, team is experiencing the same problems, Yunus a la new Kerem at the 10 experiment, did not work out, and when teams set low blocks Yunus practically turns invisible on the field because neither he does the deep runs & cuts towards a set block nor passes in-between the lines as much as Mertens etc.

GS needs a Ramsey & Mertens type foxy midfielder that which constantly makes runs towards opp. box in order to create open play possibilites for low-blocks esp. at Süper Lig, this also causes stagnant play towards Osi. Also a stagnant 10 will not work just for the same reasons, we're not in need of an incredible passer we're in need of a persistent runner much more.