I think he is still recovering from that 18/19 season - physically as well as mentally..
The main problem we have right now along with the attacking front three (who can't score more than 1 goal after the first game against wolves) - is that our attacking midfielders lack energy and pace - which we were used to during 17/18 and 18/19 season. Debruyne is great but Gundogan and Bernardo look so fragile and slow that our midfield isn't as solid as we would want to..
I remember how Bernardo played there two years ago - running 15 kilometers and fighting and tackling and always demanding the ball...
Pep should try Foden definitely - he is the best attacking midfielder right now in the team - after Debruyne..