I think the technology is fine. The issue is definitely related to your second point above. You just have to look at all the back and forth from last weekend where referees, ex-referee's, ex-players, pundits and punters all had different opinions on what various calls should have been. So tackles, a lot of handball situations, hairline offsides, penalty calls or non calls will not necessarily be resolved by VAR. it needs to be used more sparingly and specifically when it can show a clear obvious error. Following from that, there should be a very short time limit to present a contradiction to an on the field call because if it’s obvious and clear you should see it in a couple of seconds.