First of all, they have zero incentive of selling him. That makes him already more expensive than his usual market price.
Secondly, who would they buy for this fee to increase their squad's strength? Because the only reason they would be willing to sell him is, if in return they get stronger, not weaker.
Third, they have no problems with the ffp, nor are they in need of fast cash injections. We on the other hand have problems.
Fourth, we're their direct competitor and they, and more importantly their fans hate us, which means to sell this possible sale to them, it must feel like they've cheated us, as it was with Griezmann back in the days for 150m, which will make him ridiculously overprized.
These are all arguments against.
PS: And why are we even discussing 100m+ pricetags, when we're barely registering 50m players. Even if we return back to 1:1 in the summer, it doesn't mean we can sign freely. It means we have to free up 100m first to register 100m.