I hope that Erik ten Hag's purchase of Andre Onana is the best choice and will defend his goal very well, but in reality I think Andre Onana is very bad as a Manchester United goalkeeper and always concedes goals.
And Andre Onana during his time as Manchester United goalkeeper has conceded 12 times in eight matches in the Premier League, and apart from that in two matches in the Champions League he conceded seven times and only kept three clean sheets in all competitions.
And I agree with you, if Manchester United's defense is not good, at least Andre Onana is a hero who should be able to guard his goal very well. But in reality he is not like that and I prefer David de Gea to return to Manchester United.
Onana was a good goalkeeper for Inter Milan, while at Man United everything was heading towards failure.
Ten Hag finds himself under great pressure, even though he is quite confident that he will not be fired by United management. As a club that has a fairly large fan base, United has received quite a lot of attention regarding their performance this season, especially players like Onana. It is very unlikely that De Gea will return to Old Trafford, Ten Hag must be able to convince United fans that recruiting Onana is the right step, we know it will take a little time but I think the adaptation process has been quite long.
Ten Hag really has to look to the future and is required to be able to bring his squad to achieve good results in the next matches, his chair could shake again if he fails to get United through the UCL Group phase. Sheffield United, Copenhagen, Man City and Fulham are their next opponents, I find it difficult to predict which matches The Red Devils can win.