I dont think theres any problem with VAR in itself. The problem lies with the same corrupt/ and/or terrible refs monitoring the VAR screens.
Yep, this is it.
VAR is a brilliant system, but if it's left for individuals to decide as and when it's used, and still gives biased officials the opportunity to turn a blind eye even with all of the evidence laid out in front of them, in multiple angles and with the replay sped up, slowed down, etc. then it's useless.
If a VAR official decides he doesn't want X team to win in the game he's got the authority to give decisions, then he can single-handedly and very easily influence the result of the game, with no repercussions if he gets decisions wrong or blatantly ignores fouls, etc.
We saw it at the weekend with Lukaku's extremely marginal offside (couldn't spot with the naked eye, all of the angles suggested it was about a few millimetres at most offside, if at all), Keita's studs up tackle going completely unpunished. That's a goal chalked off for Chelsea and Liverpool not being reduced to 10 men like they ought to have been. For the van Dijk offside, it was impossible to give the goal as the lines on the screen said it all.
With all that in mind, I don't see how VAR will ever work in this country. It's too open to cheating, biased officials, officials being given back handers, etc. There is too much money being made from the big clubs for the FA to want any of the smaller clubs to take one of their places.