Manchester united might just consider David De Gea contract instead of buying Onana with huge sum of money, since the transfer cash available for Ten Tag are less. expect the Qater taking over the club happens before the end of the transfer market, then be assured Manchester united will bring in Onana and other big stars. But if it went the other way round of having the Glazer's family as owner, then expect nothing from the transfer market. Inter Milan is ready to sell Onana this season, if they see any good offers.
The management therefore made the decision to cut De Gea's wages in half if he agreed to sign a contract extension, but I heard that De Gea has rejected the offer because he did not agree to his new contract which lost half of his salary. I understand that Manchester United don't want to lose the legendary goalkeeper but on the other hand, Ten Hag also thinks that they need funds to welcome the transfer market this summer, therefore the best solution may be to cut his wages. Because yes, as you said, apart from goalkeeper Ten Hag, he also needs several new quality players to welcome the Premier League next season.
We all know that Ten Hag really wants Onana and so far Manchester United has made his first offer, but I heard that Manchester United has been rejected because Inter will only sell Onana for 60 million euros including bonuses, and the first offer made by Manchester United is worth 40 million euros. I don't really know whether these negotiations will continue or not, if Ten Hag really needs it I don't think there is any reason to cancel this agreement.