Having looked at it a few times I think VAR has to overturn it and they made the right decision.
Initial contact looks to be outside the box.
Fouls continuing into the box according to Law 12 have to be holding offences. He’s not held him, just impeded him so first contact is what matters for this type of foul.
Clear and obvious isn’t relevant here. It’s a line decision, has to be either inside or outside. Like offside it’s not considered subjective but binary. Tricky but looks more out than in so it’s pretty much the only decision he can come to.
The VAR official has just followed a simple process there and I can see why that’s the decision he had to make.