The goalkeeper should read the team as well as the space ahead.
A quick release is useful when teammates are already facing forward, the opposition are disorganised and you have a clear numerical or positional advantage.
If your full-backs are still inside the box and midfield are recovering towards their own goal, the quick throw may simply give the ball to a teammate who cannot play forward.
I’d give the keeper a simple check: do we have a player ready to receive facing the attack?
If yes, release quickly.
If not, hold it for a few seconds and let the team reset.
Practise both outcomes after crosses in training so the keeper does not feel that “quick” is always the brave or positive option.
Good transition play is about exploiting disorganisation.
If your own team is the more disorganised side, slowing the restart can be the better attacking decision.