First you have to break the ego of PGMOL and they should welcome criticism before anything can change.
They should be more transparent in the exchange between match official on the pitch and the var official, and when they make a wrong decision they should defend their decision openly and accept mistakes. The idea that referee's need to be protected has gone too far...and we need to turn around and ask why? Because it is stopping the better use of this technology....we are in a situation worse than without using the technology.
Clearly that isn't the case, ridiculous onside/offside decisions, by metres, have gone,as have offsides against the wrong player and a number of other pertinent situations if not totally resolved then at least now rarely mismanaged. However the implementation is beyond absurd and verges on dishonest.
What is frustrating is that the VAR management have had months (Covid closure) to sort this out and implement rules that everyone can understand and accept.
1. Hands & Arms can't be considered offside. This has nothing to do with 'can you score with them' but purely because they are used for balance, that isn't an unfair advantage.
2. The frame rate MUST be considered (and funding given to implement the 240 fps cameras UEFA recommended). Therefore there must be a margin of error (yes it does just move the line but at least fairly) e.g. Mane could be clearly on-side one or two frames earlier.
3. Is the attacking player gaining an unfair advantage? Back to goal isn't an unfair advantage.
4. Where has benefit of the doubt to the attacking team gone? Reinstate it. In a tight decision advantage should be given to the attacking player, as used to be stated in their offside rules (not sure if it's still there, it was a few seasons ago).
Four simple considerations that almost everyone could accept. Yes #3 & #4 are a little subjective but then so are many other decisions in football. As has been said, this adherence to the mm is contrary to the spirit of the game.