there are many ways to find out if the casino is a scam or not and it is more effective if you use a small deposit method and try several bets and try to withdraw funds and do it several times. because usually the first withdrawal is successful it can be just bait to deposit even more funds.
only it's a more effective way than reading reviews alone, because many fake positive reviews are published on several sites and pay for each positive review.
doing your own research is much better.
A scam casino doesn't necessarily need to delay your withdrawal but they can use different ways to do that which you might not notice initially, for example, a casino that plans to scam their customers will simply not let them reach a point where they can request a withdrawal since they will have their games rigged and you will eventually lose everything whenever you are about to reach the point where you could withdraw the winnings.
Such casinos are caught but not initially, after some time and only by a few players who are good at observing things around, otherwise, a normal player would never even have a doubt, all they will think is that they are unlucky and not winning at all.
A scam casino is not going to use only one tactic in order to scam their customers, once they have decided to go that route then they will use every single trick available to them to scam their customers, so if for example a gambler makes a bet higher than their average bet then they can manipulate the results so the gambler always losses that bet, they can use their TOS and interpret it freely to accuse their customers of cheating even if this never occurred, they can claim the user was hacked and that is why there are no funds on their account anymore, once you begin to think about you will realize there is no end to the number of excuses those casinos can use to steal our money.