We need to come off this "only British players" are worth signing trend. Well, except for Sancho, he might be worth it but if you had to go for either Graelish or VDB, it's gotta be VDB. Graelish bottled it vs United and doesn't have the European experience we need to go for more trophies. VDB has already played a fair bit of UCL football and would look smart in our midfield. If we rested Pogba or Fernandes (or with how Rashford is playing MAYBE Rashford) and put VDB on, we don't lose quality on the pitch.
There could be some truth to other clubs waiting until they're done with European football to conduct their business (aka Smalling to Inter or Memphis to Dortmund rumors). This ends soon. Either way, this either provides us with additional funds to stump up more of an upfront fee for Sancho and/or Dortmund feel they have cover on the wing if Sancho comes to United.
Going a "little too deep" in the weeds...say Sancho is our priority target this summer and we can believe that personal terms have been agreed with Sancho and there's a general agreement that should we table a reasonable offer, Sancho will let Dortmund know in a professional way that he wishes to join Manchester United AND there's a general agreement that Dortmund will accept guaranteed installments with a larger chunk up front...then it actually kind of makes sense to ensure that we have the first installment ready before we negotiate these deals. Say we also wanted VDB (about 40m maybe?), we have however much cash on hand + access to revolving credit. I'll assume for sake of this scenario that the financial folks at United know how much we need to pay staff, etc (something United have done well over the course of COVID-19 unlike other English clubs). There's also money incoming (or at least not money owed) for our re-qualification for UCL. It COULD BE SAID that we're waiting on some incoming funds before we bid for others (Gabriel or VDB) because Sancho is the deal that United have decided should not be jeopardized.
All pure speculation of course. Who really knows with our transfer team at the wheel.