I think OP is looking only on a site that offers provably fair? Most of the gambler owners are smart now, their strategy is not to limit their gambling site with one option right now they have provably fair, casinos and sports and esports I am not sure if you are looking for something as there's a lot of existing ones.
I think if @OP could pick a casino that already has a good reputation he needn't worry about being proven fair because that casino will definitely keep its reputation and won't cheat gamblers playing in its place. Thus, @OP can play gambling calmly and can focus on the gambling game he chooses. If @OP suspects that the casino is not proven to be fair, then @OP can directly discuss with customer service and ask there.
Yes if the casino is reputable I am sure that he shouldn't worry. I think the op is not aware that most of th gambling site we have now have their own original games with provably fair algo although some casinos have only games from other service and not provably fair.