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.
If gambling is legal in that country, the government has no right to ban anyone from advertising gambling because they are the ones who allow people to gamble by legalizing it. So it is unfair to influencers to suggest that the government force them to stop promoting gambling.
In my opinion, if the government has legalized and taxed gambling, they must take full responsibility in helping people have the right perception about gambling. In addition, to implement more effectively, the government needs to coordinate closely with casinos (enterprises) to manage and force casinos to comply with regulations.
On the other hand, government can not tell their citizens how they must spend their money. The problems with teens and gambling is not because teens, kids or adults gamble, but because they dont realize risk of spending too much money or chasing losses. The same might be with person going to a shop and spending all his money on goods. Same problem, recklessly spending money without thinking about future. I dont quite get how government can control or coordinate people, and force them not to spend more than they could.