I lost almost 7 btc on several gambling sites and then I got the idea to create one but to be unique. Now I have 15 BTC available to invest in a site like this, but my experience with designs and what games might attract more players is small. That's why I decided to ask here because I know there are many players. The site I would like to be for your preferences.
I think 15 btc is just barely enough to create a really competitive site nowadays
at least a casino that can compete with the likes of Stake, Bitsler , crypto-games etc.
by the way , unique doesn't always mean profitable , it seems like the most successful sites nowadays are pure dice sites ( or casinos based on dice + some more games to spice it up)
just have a look at the dominance dice shows , it is both the most gambler's loved game due to its simplicity and pure math and a very easy to implement from a devs point of view
for a casino 10 btc bankroll spread between 4-5 supported cryptocurrencies is a bare minimum and even then you are risking a wild whale coming and beating you , bankrupting in the process assume 5 btc will be the development costs and the initial salaries of the moderators , support , designer etc.