To be clear, when I say subjective decisions I mean everything other than offside, goal line technology and instances of mistaken identity. Even with offsides, the subjective element I'd leave to the onfield officials, only using the tech to determine whether the player is in an offside position or not.The problem is it becomes subjective as to what a subjective call is, I mean pretty much all straight red card offences are subjective (was it violent conduct, was it a goalscoring opportunity, was the handball deliberate etc) to some degree, but people get incensed when general concensus is a card was given erroneously.
Offsides you sometimes have a situation where it really isn't clear, so "make whatever the correct decision is" becomes subjective i.e. one person says its offside and someone else doesn't, one person gives a penalty and another doesn't. We can use this forum as an example, we frequently have differences of opinion about onfield decisions.
If we want to completely eradicate subjective decisions from VAR you basically end up with it not being used because there's the potential for nearly every decision to be subjective.