It's more a question of profiles rather than of quality. We need a winger who can give the team width and 1v1s and Nico even if flawed does that very well.
Things clicked better with Dembele for that reason. Even though he isn't an amazing player he had specific qualities that helped that team's dynamics like the fact he was the only player with strong 1v1 abilities and true pace.
You need those players to push back the other team's defensive line and to create space for your team.
Whilst it doesn't have to be Nico and I agree Nico is not world-class either he would still help the team significantly for those reasons. We need that type of winger.
I've seen the light and Olmo will be decent at left wing with an attacking fullback for a season until Nico potentially arrives.
But I'm mostly disillusioned by getting rid of Xavi for Flick and then focusing on a signing that doesn't maximize his flow of football.