What a horrible start for Onana, to think he was one of the best goalkeepers in Europe last year.
The hype is what has gotten you disappointed so far. Before he moved to Manchester United, there was plenty hype with the news, but what do the fans really want? for him not to concede even with Manchester Uniteds.poor defence? he is not super man. Onana is just a good keeper with extra passing ability which sometimes becomes a problem also for him, a little wrong decision making in his position which is always a critical one can put his team behind.
The opportunity for Onana to keep a clean sheet must be supported by a strong defensive performance because if their defense is weak enough then Onana will experience bad luck in every match. Like what happened in the Arsenal vs Manchester United match where in that match Manchester United's defense was quite bad because several of their defenders were injured which made their defense line not very strong. So that when there is an attack from an opponent they are overwhelmed to block it. I'm sure Onana will be able to make a contribution to keeping the goal from conceding in every match, but he found it difficult to do so in the early matches of this season due to their poor defense this season. I'm sure criticism of him will not be too suitable to be thrown early on because he needs time to do his best like he did with Inter Milan last season.