Yep. We must admit that Man United defenders often played badly. The problem of Man United defense is actually on the defenders, not on the goalkeeper. It is because it already happened since De Gea was in Man United. People blamed De Dea at that time, but they just realize it now that De Gea shouldn't be blamed because the real problem is on the defenders. It is proven that Onana also experienced the same thing, there is no change on the defense strength. I don't know why Ten Hag never choose the right defenders when he buys new defenders in the transfer season. I sometimes assume that Ten Hag looks not really care about building Man United defense line. He is too focused on building Man United front line and midfield line.
In my opinion, Manchester united lost important players in their defense due to injuries such as Lisandro martinez, Malacia, Shaw. So their performance this season is considered a crisis in their defensive line because several of them have to be absent for a long time to recover from injuries. This is what has had a negative impact on their performance this season, but apart from that, of course Onana performance has been criticized by Manchester united defeat in several previous match. because Onana status is as a substitute for De Gea, whose performance the fans really pay attention to.
And apart from that, of course, if you look at the overall performance of Manchester united players this season, it is not very impressive in every match. Several players who were quite influential last season experienced a setback in their performance such as Rashford. I think Manchester united players must be able to improve their quality to be able to support their performance this season.