I mean you could get both for 40-50M in fees (not counting Ramos signing bonus). If United hold out till end of the window I dont see why PSG wouldn't try and swoop in if Varane persists on the 'new challenge'.
As Birdy said, you need to act according to the hierarchy of the needs. PSG have historically weak fullbacks/wingbacks, even more emphasized under QSI with the top quality players playing alongside them. Kurzawa is straigth trash and Bakker was supposedly recruited to do business with Raiola when we were in for de Ligt (Raiola met Antero who got fired the next day and Leonardo apparently shut down de Ligt case). Both are weak and our starter isn't a footballer right now but a patient.
In CB position, you will have Marquinhos, Ramos, Diallo, Kimpembe. Diallo is actually more talented than Kimpembe but we call him "soft Diallo". Kimpembe put more impact in his game and Diallo is always injured. I guess we still have a problem because Marquinhos is the one playing right CB and the other ones are more of left CB. Kehrer could be a right CB but the guy is so... i dunno, he is a walking mistake and apparently, the critics from the fans have destroyed him mentally according to reports. It was said that he wasn't even good enough in training these days and we prefered play portuguese Danilo as a CB instead of him.
The problem here is you think PSG can just keep buying players but PSG don't have unlimited money. It is said by close sources from the club that they will need to sell players to keep buying. So if no sale, prolly the window is over after Hakimi and the free signings (Ramos, Donnarumma and Wijnaldum). PSG are trying to get rid of the useless players but it will be next to impossible because they like their contracts. The easiest to sell would prolly be Sarabia. Players like Kehrer, Kurzawa, Areola, Rico, Herrera, Paredes, Icardi will be sold if a correct offer comes. Midfielders are especially what they hope to sell to try and buy Camavinga or Pogba.
Next, there is the problem in attack. Kean was loaned from Everton last year and contributed in a good 20+ goals the season. Everton don't want to loan him out again. We will need to cover this loss by spending a bit of money there which means the prospect of seeing a player like Theo coming in is very low. Di Maria doesn't have competition/successor too. We just have so many holes to fill...