That was the greatest mistake Manchester United has ever made, by selling De Gea, just like you said the best thing they would have done was to retain him and keep Onana as there main goalkeeper since they choose him over De Gea, I believe they are facing the consequences of there action now.

I now that by now Manchester United is wishing not to have sold him because even the Onana they thought was better than De Gea has now become there begest mistake because he is not helping the club at all, but come to think of it Onana was doing very well when he was playing for AC Milan, so the question is that, was it because of the club that made him performing that low or ordinarily he is no longer the goalkeeper we use to no?