my guy, city won the title last year without aguero. grealish is better than sterling, foden, silva and mahrez. them not getting a striker is not related to buying grealish. did they need him? not necessarily. is he a big upgrade? of course he is, he was a top3 player in the league while playing for a trash team.
rodri and kdb are not even forwards, they are midfielders, idk how clueless you must be to compare them to grealish.
also, 100m is a fair price considering english players cost way more in the premier league. did you expect him to go for 70m as an english man? as i said, you are clueless