There is no loophole. You can't offer gambling services in
Hong Kong. You're looking at up to fines of at least 5 million HKD and a few years in jail. Maybe
Hong Kong authorities won't come after you if you don't target local customers, although I wouldn't count on it.
Hong Kong has a pretty effective rule of law. Without a license, you will in most cases be breaking the law in the countries where your customers are based.
Without a gambling license, you will struggle to find
payment solutions. It's practically impossible without knowing the right people. Once you do find one, you will quickly learn that many are going to vanish into thin air and run with your money, because they know you have no legal recourse.
If you're serious about starting a gambling business, the very least you could do is whitelabel someone else's license and let them handle all the difficult payments, finance, and compliance stuff. If you have adequate funding, you could look into getting your own license.