Ralf Rangnick coming out and saying that Goalkeeper is the only position that you don't need to strengthen makes me seriously doubt his judgement on modern football.
De Gea is an all time great of Man United and the Premier League, there is no doubt about that. But he's much more of an old-fashioned shot-stopper than a modern day 'sweeper-keeper'.
Of all the other traditional top 6 teams, their goalkeeper's 'sweeping actions' for this season are all amongst the top 10 (Alisson 25, Lloris 22, Ramsdale 20, Ederson 17, Mendy 15).
De Gea is 16th on 6.
Until this season, I hadn't really seen what a difference having a modern 'sweeper-keeper' could make. At the start of this season, my team Wolves got rid of Portugal's legendary goalkeeper Rui Patricio and replaced him with an uncapped Portuguese player in Jose Sa. Believe me, this didn't go down very well at all at the time.
Patricio was another goalkeeper in that old-fashioned shot-stopper mould. He was great for us, but there was a stat to show that he was the goalkeeper that left his line the fewest times in the Premier League during his time here. Ideal for Nuno's tactics of sitting in and counter-attacking, but less suited to a team trying to push higher up the pitch.
Sa changed this, how wrong we all were about him!
For the early part of the season, Sa's sweeping from goalkeeper transformed how we had been playing under Nuno and pushed us much further up the pitch. He even got an assist with his fast kicked passes. Yes, we have other issues at the moment with our forward players, but goalkeeper is far from a problem for us. Sa is a modern, sweeper-keeper who has been taking many plaudits this season for how he has been performing. He is top for 'goalkeeper sweeping actions' with 30 for this season so far.
As great as De Gea has been for you over the years, I think his goalkeeping style might be holding you back a bit now.