Sorry only read it today, wasn't it already confirmed for PSG or there's something else on it?
Regarding the player itself as you know he was one season at Wolves on their last season under Nuno and fair to say it didn't worked out that well for him, suspect at the time outside Neves and Moutinho he didn't trusted anyone else for that role, even tried a moronic number 10 role for him which made me doubt Nuno really knew the player and wanted him there. Of course being Mendes his agent perhaps his opinion didn't counted that much.
Shortening this, he is a number 8, not really the type of player who scores a lot of goals or makes a lot of assists but would say has a good decision making level, improved his work rate to recover the ball and press more and was recently promoted from the under 21's to Portugal main squad.
Don't know if United is or was interested, more important than that if Ten Haag is interested, I suspect from his Ajax teams he likes that type of player, but of course from United point of view De Jong would be the prize for the midfield role.
More than the type of midfielder who would show up on the highlights for being a goalscorer or making spectacular assists he is the type of midfielder who makes the things happen, some similarities with the Moutinho of 10 years ago, maybe not as strong tactically but more stronger from the creative point of view.
If he goes to PSG it will be based on Luis Campos, if he will suceed there it's another conversation, guess it's the best information I can give to you.