§8 (10) MStV:

Werbung für alkoholische Getränke dürfen den übermäßigen Genuss solcher Getränke nicht fördern

Advertising for alcoholic beverages must not encourage the excessive consumption of such beverages

Of course, that's vague AF to the point where you can argue both that anything but "Hey let's portray binge drinking as cool" is a-ok and on the other hand that portraying any kind of positive association with alcohol is not ok. And considering how the regulators somehow refuse to shut down right-out scam call-in shows there's not much hope for them to interpret that in a way advertisers would disagree with (advertisers have their own rules because shitstorms against their behaviour are not good advertisement).

Talking about political strategy though, I don't think that's a particularly good point to start, the first step should be warning labels, akin to tobacco. And yes I'm completely fine with the same kind of labels on coffee and tea and while we're at it ultra-processed food.