I say let the coaches have the right to initiate a VAR review. They inform an official they want a certain moment/decision/action reviewed. As long as the review gets resolved in their favor, they can keep invoking VAR. This would disincentivize review spamming, disrupting play. If there are too many VAR calls in a game, you can squarely blame the ref.

Coaches get in the face of the officials already anyway. This just gives the action a chance at being productive rather than an opportunity to get a red card.

Yes, this is based on the derided review system of Olympic Taekwondo. It's horrible in a fight sport but football is a ball game; somebody tell Paredes and Paraguay please.