I still don't see how he fits in. You needed to replace Sane to stretch the pitch especially with Cancelo at LB. You're still way too congested in the middle.
Sane hasn't been that guy for City since their first title winning season under Pep. He was getting benched by B Silva and Sterling the following season.
Yes, the amount of pace in City's play has dropped in that time frame. But that's mostly due to teams electing to cede possession and allow City control of the ball outside of their own 3rd. Most teams drop back so deep, that they have defenders on the far side to stymie any quick switches to the opposite wing.
There is only so much you can run into a parked 747. It's no surprise that Sterling has struggled with City's evolution over the years into a more patient probing system. That's why we are struggling under Ole now that teams are denying us space to counter.
The false 9 was a temporary solution that got City a league win and CL appearance last season, but teams for the most part are more hip to avoid being dragged out of place when a Foden or KDB drops deep, which results usually in a semicircle of City players around the box.
A dominant 9 who could pin defenders in the box (while being able to contribute to play generally, so a Lukaku wouldn't be optimal) would potentially create more space. But a reason for City's dominance in overall play is precisely the lack of a target man. So does that leave them better off overall? Also, the focus on a striker detracts from the point that overall, they are really bad at finishing chances. Either way it will be interesting to see how they continue to adapt.
Regarding Grealish's use to City, if you view him as a long term replacement for D. Silva (his ability to playmake in tight spaces at the right pace and moment, or pausa, was so integral to the way City unlocked opponents) then his phasing in makes sense. He needs time to adapt to City's system, but he can't do that in bit part appearances. I imagine that once he is up to speed he'll be moved into midfield. Rodri had a rough initiation being placed into midfield and City suffered for it in the 19-20 season; he's fully up to speed now and very people say they miss Fernandinho now.
The transfer tag will detract from the fact that so far he's done well. If his trajectory looks anything like Rodri's or B. Silva's or Cancelo's... There'll be a lot of egg on face come next season.