I certainly see the risks with a review system, however I think the main benefit is that regardless of those risks, it takes the burden off the referee!I have also been a long time Advocate of a review system.
Although, it would still seem unjust if a team were out of reviews, particularly if the lost reviews were subjective decisions, where, say you and I had a differing opinion on what offence, if any was committed.
I really don't think there is a perfect system.. Whatever protocol is in place, there would be some fault with it, where some team or other would face unjust consequences.
I agree with all your sentiments though, but, whilst the current debacle is avoidable by changing the system, any alternative systems I have seen suggested tend to have their own difficulties and challenges (no pun intended) as well.
I've seen quite a lot of use of the review system in cricket - and one thing that's very common is for commentators to criticise the captain/batsman for making a bad review. Games have been won and lost because captains have used up their chances in a speculative manner. But even when the umpire makes a howler later on, it's the captain who is criticised for his decisions that led him to a position where he didn't have a review available when he really needed it. As a referee, that's WAAAAAAY better than the current system where anything and everything comes down to "f****ing VAR"!