In a team sport the only stat that ultimately matters is results.
I saw an article around a year or so ago that had Jack top of a players points per game chart, presumably because Rodri was involved in more drawn games. So you can be as sniffy as you like about Grealish winning free kicks but retaining possession high up the pitch helps City sustain attacks and thus helps the team's attacking and prevents counter attacks which helps the team's defending.
It's bizarre and absurd to claim Grealish "hasn't been a success" and has been a "massive disappointment" as when Grealish is in the team City tend to win more and when he's not in the team City tend to lose more.
Which is why Grealish:
- played the majority of PL games in each of the 3 title winning seasons he's been here
- started 12 of 13 games and came on as a sub in the other group game in City's CL winning campaign becoming the only £100 million pound player to win the CL for his new club
- has appeared only as a sub for 20 minutes at 3-0 down in the 5 defeats this season