Explain how he is performing terrible this season? Is it because everyone expects a striker to score and Jesus have scored just 4? IMO he is performing great even though he doesn't have much goals. You know why Gundogan have so many goals? because opponent team only focuses on their attackers and wingers especially they keep on checking the run of Jesus and properly mark him. Guardiola has given the license to Gundogan to go up ahead and make run and he does when Jesus is checked and no one pays attention to Gundogan properly and that's how they have been scoring. Check all the previous matches you will find Gundogan always making a run or urging to make a run. If yes he Jesus have been given role to make all the runs and shoot only then yes I would have agreed that he isn't performing his role properly but right now he is working according to Guardiola and he is doing very well.
Guardiola has been using a very nice tactic by not fully depending on G. Jesus. I can support the idea that he is not very very good at finishing but he helps his teammates (especially Gundogan) so much to score many goals. If he used G. Jesus as only a scorer, things would be much different than now and maybe City wouldn't even have such a performance for a long time.