May I suggest just requiring people to register what how much they want to gamble and then be locked into that. If you want to gamble for 100 usd per month, then you can't bet more than that. You should be able to set your own amount, but any changes should only be active from the next month.
This has minimum impact on personal liberty, and will almost eliminate problem gambling.
Problem gamblers will find ways around this regulation. It’ll reduce by adding friction but problem gambling existed before gambling was legalized.