That's why i would like to know what's the best VPS to launch a crypto application such as casino, exchange, mixers and others.
In general, it comes down to specification of the software to run your service (whether it's casino, exchange, etc.). For example, it needs big storage or RAM where smaller VPS provider doesn't offer such option. But for application (such as mixer or Bisq node) where privacy/anonymity is most important, you shouldn't using third party usage.
VPS may have many benefits, but I have a feeling that quite soon (especially in the case of success of your project, what I wish you) your server might be insufficient for your needs - you may want to add new software, node, SPV/LN server etc. It is more expensive, for sure, but why not look for dedicated server?
Being monolithic (all application in single server) isn't always better option though.