I'm totally surprised with Andrew Onana's poor performance at Manchester United because he was so good when he was playing for Ajax and Inter Milan respectively, but he couldn't replicate the same performance at Manchester United. It already too late for Andrew Onana to join another club because the transfer window has end. After Manchester United signed new goalkeeper, Andrew Onana have to accept his fate as Manchester United second or third goalkeeper this season.
Andrew Onana is one of a number of players who have seen a decline in performance after moving clubs. Real Madrid investment in Hazard was similar to Manchester United investment in Onana. It's hard to understand what Onana, who plays as a goalkeeper, is going through. He shouldn't have any problems even though he has moved clubs, but now he will have difficulty getting playing opportunities after Man United brought in a new goalkeeper.
After losing his position as Man United main goalkeeper, he will have a hard time attracting interest from other elite clubs to recruit him, perhaps he will deeply regret his decision to accept Man United offer, but that's the cycle that occurs in a player's career, no one can predict what will happen in the future.