It is somewhere in this interview/discussion between Andy Mitten and Mark Ogden.
https://audioboom.com/posts/7246065-uws-podcast-380-mark-ogden
From memory, Ogden said De Gea is a talented keeper but his style of keeping seems out-dated compared to the approach taken by Ederson etc, coming for crosses, sweeper keeper, ability to start attacks. While United fans rate De Gea highly, he wasn't convinced that the rest of the world sees him in the same light. Questioned whether De Gea was really worth the type of salary he appears to be demanding. Basically thought United could replace him without too much damage. (I listened to it last month so I may have missed key aspects of the discussion). Andy Mitten didn't express much of an opinion either way, though he did mention United had made a huge offer to De Gea that got rejected and that United considered the agent's fee to be outrageous.
I expect De Gea to be at United at the start of next season, regardless of where he would prefer to be, simply because the big clubs will have been frightened away by his horrific performances this season. Real Madrid have not been interested since the Fax fiasco. PSG or Juventus might be interested in him on a free transfer, after a good season, but not now when a significant fee would be involved. They don't want to blow their CL chances by recruiting a keeper who let in Messi's tame shot and made a horror error in the World Cup. Imagine being the Sporting Director of a serious club that recommended buying De Gea right now.
De Gea will take his time, see what his options are, then make a decision. If it's purely a financial one, then I suspect United's offer will be far superior to that of any other interested club. If he wants to move back to Spain or try a different country, then I'm sure he will get offers that will appeal.