Zaha is 26 too.
The more I watch Ziyech in AFCON, I think he is not the most pressing need we have. He cuts in too much to play in the middle and don't stretch defences. We don't really play combination football to get our midfielders in shooting position anymore after Wenger left, Ziyech wouldn't thrive as much here as Ajax.
The one player I am really impressed is Bennacer though.