To be honest, I saw a lot of new casinos with amazing sites and even licenses, but so far I have no confidence in them and only test their free games where possible.
To enter real money there I must be 200% sure that there will not be any problems. and this is difficult to understand because there are very few reviews on new casinos.
If you find a new casino as more amazing then existing ones and you had great experience with their free bets as well then if you afraid of not having many reviews about them then you can simply try their legitimacy with very minimal amount because every popular casinos are started from the scratch who knows you found another casino which is going to be popular in future.