Normally, every club looks out for what's best for them. While some decisions, like letting Da Gea's leave Manchester United, might not seem like the best decision, from the club's perspective they were probably thinking they were making the right investment. And now, they're looking for a way to bring him back and letting someone else go. It's just about trying to move the club forward.
Imagine the player they want to replace having to start praying another club buys him. For me, it De Gea choice, he would look at the club that treated him well, paid him well, and respected him, and make his decision. If he decides to go back to Manchester United, there's really nothing more we can do, it's up to him.
What do we have here? De Gea coming back to Manchester United? That's the worst speculation I will ever accept from Manchester United, first I think the headline is wrong. They admitted their mistake, if they really are and want to brings him back, this will not be the headline and Secondly it will be a shameful thing to brings him back a free transfer, like it's the audacity like they owned him, this is not happening and I'm very sure man is coming to that helpless club.
There are far better players to be replaced with De Gea but I don't know who advice Ten Hag to signed Onana, probably the good time of 2021 Champions League overwhelm them and didn't do due diligence, they should look else where and recruit a better goal keeper like they recruit De Gea before his prime. It's only someone with better ambition that can change Manchester United, if they brings in a player that is not hungry for success, they will experience more of Onana and this time even worse.