Just my personal impression based on his appearance and the way he behaves in defensive 1-on-1s. I think Zinchenko looks as powerful as FDJ, and he regularly gets outmuscled by wingers. Another reason why FDJ won't be a DM: his trademark moves suit СМ/AM more, he's not a 'sitting' mid, shakes off opponents by accelerating into space, not by footwork.
I like both Weigl and FDJ, but don't see 'complete' DMs in them. Ideally, I'd like City to find someone combining Weigl's press-resistance with Dinho's ability to press across the pitch. That's why I've used Rijkaard as an example, the guy had Vieira's athleticism and pirloesque passing in one package. I know Pep sees the game in a different way, collective defending in his view replaces individual ability. But I'm still getting jealous watching that Milan side packed with defensive superstars (Rijkaard, Baresi, Maldini etc.). Really can't see anyone close to them in modern football. Perhaps Fred could be the solution, but only time will tell.