It needs to educate the influencers so they will not promote gambling to public and there are a strict rule for them about promoting something. If the government can cooperate with the influencer and gives education to their citizens about the risks of playing gambling, maybe that can works and the citizens will not trying to playing gambling.
And for physical casino, they must strictly limit people and will not allow teenager to enter to the casino although that can not be apply to the online casino but the online casino can use the other methods to prevents teenager to playing gambling.
How can you have an impact on influencers if casinos pay them? Get payment and say opposite? And I doubt that government will be involved into that. They receive taxes from casinos/business. Government can say that casinos are bad on public, but continue selling licenses and collecting taxes. Its similar situation to alcohol and tobacco. You can make million warning signs, hide or cover them in the store, prohibit advertisement on TV and on public, but they still we be on top of sales. Long story short, you can do whatever you want, but only working solution is to change society, which is impossible.