I'd be tempted to put in an £80m bid and just see if there is anyone else who fancies shelling out that kind of money in the current market. I don't see any foreign clubs being able to come anywhere close to that. I don't see United paying that as they have other positions that need strengthening. Liverpool won't pay it either. I just don't see a big market out there for him, for what Spurs want.
Chelsea might be able to do it, but I suspect they might want to give Tuchel some money to bring in "his" players first.
Spurs won't be able to turn it down without risking having an unhappy player who could just leave for free at the end of his contract.