It's hardly surprising that two well trained FIFA refs are usually going to have the same view on the video when the first is only going to the second if the first thinks the answer is clear and obvious. Close calls should never be going down, so disagreements should be unusual. Nonetheless, we have already seen one R disagree. Those occasional disagreements are also not surprising: the VAR and R are going to be separately evaluated on their own decisions. The R doesn't do well on his assessment by accepting what the VAR said, he does well by getting the call right. He is not going to take a hit on a KMI out of "courtesy" to the VAR. The refs at this level are not wallflowers.
The R also looks at the video to make his decision on any judgement call, so your premise is incorrect. I think you grossly underestimate the self-confidence/ego of high level refs if you think they will passively change their call because of what someone else thinks.
Especially when it's a Spanish ref who's well known (for better or worse) for being the center of attention in many of his matches. He wouldn't bite the bullet just to not hurt the feelings of some American ref.
I think the fact that we have a 5 page discussion over the merits of one play should tell anyone that referees are just as willing to not take each others opinion just as quickly as they would welcome it.
I have no idea what goes over the headsets at this level, but one thought: that’s Mateu Lahoz’s regular AR crew. The AR on that play may have had a better view of the defender’s body position than the center. Maybe Mateu Lahoz gets word from both the video referee and the AR.
I think a point to add from what I have learned from watching MLS vid's of VAR is that the VAR's are judged on how they send the clip down and speed of editing. For example, they can zoom in so far and send down two clips (In MLS *not sure about WC) one with the zoom one with a different camera angle of lets say behind the goal. The assessor will see if those were the optimum camera angles and judge the VAR on that. They'll also look at the speed in which the VAR makes a decision to send it down to the referee etc etc.