Having enough funds shouldn't be the only thing to focus on. Putting up a casino isn't an easy thing. It would require your skills and knowledge of this business and be honest, establishing a reputable casino will be hard if you can't meet the standards of most players. You have to make sure that you're also able to meet all the requirements needed to run a casino and where to get trusted people who could help you run this business successfully. You could risk a huge capital but you might lose it if you are not knowledgeable enough about what you are doing.
and there's marketing that is an endless spending of money for the casino to stay visible to users. you have to have deep pockets to make it. influencers are not asking tiny amounts of money to promote a casino. the casinos that made it to the top and stay on top for long spends tons of money for its promotion.
the 100k initial capital OP is saying is probably just putting a casino up and running. getting it to be successful is the most challenging for it needs more funds.
On marketing alone then it wouldnt really suffice and its true that you would really be needing that deep pocket for you to be able to climb up gradually because if there would be no exposure then it would really be still
useless.Lets say that your site is good looking and does have those best games but literally just the same with competitors around but you dont have those advertisements or exposure then people would just
simply ignore it out and cant really get sufficient number of players which would lead up into disaster.
This is why crypto gambling casino is never been that a cheap type of investment, there's lots of things to be considered.