I think you're probably right tbh. Aguero wasn't far behind for a period.
But Kelechi has been largely deprived of regular football for most of several years, which has severely impaired his development as a player imo, otherwise he might have been much more comfortable with it all. He has never had the time playing that Jesus, Sané & Sterling had.
If he plays regularly elsewhere, then he might get back to the kind of alround ability he showed before we signed him, rather than just being a prolific goalscorer.