You know that stablecoins are centralized and can be frozen and seized by those who control them? This means that BUSD and Tether are out of the question, because when your gambling site will gain enough volume, someone will notice it and your wallets could get frozen.
DAI and other algorithmic stablecoins is the only option, although you should research if they are fully immutable or also have "backdoors".
I didn't think about the volume. I think I'll stick with Tron as main deposit method and maybe I'll keep my balance in BTC. or trx. Which is the most stable coin to hold my balance? This 2 are good? I see trx is somehow stable.