The Crypto sites have large limits, but they have this ridiculous software thing where they shut you out of the game if you get ahead 8 or 10 thousand. For highrollers that can be one bet with a double down. 32 Red does have a 5k limit at BJ and they have excellent customer service and fast cashouts.
Casino Fortune can raise your limits up quite high, but they are very slow to pay. Often 3 weeks for a cashout and then it will only be a partial payout.
RTG casinos can raise the limits if they want to but the good ones normally won’t. Usually they have a max of 2 hands of 500.
I think one of the big failings of the casinos is not catering to high rollers.