We could just start making it illegal to advertise to children. Without age verification, it's just a burden of proof with the advertiser that their ad isn't targeting children and a ban on age specific target groups for ad platforms.
Salami-slicing, and appeal to a more appealing proposal and target group. Adverttising-to-children is inherently controversial, already banned in many countries / jurisdictions, and is a relatively easy sell. If there's going to be a reform in how advertising is perceived and regulated, it's less that this is where to stop than where to start.