None of that will work. Sure, have some basic regulatory model for your political campaigns to avoid unduly intervention by foreign actors and similar shady stuff,but that is an small deterrent. You cannot avoid targeted advertising, hell, all advertising is in one way or another targeted. Even if you get rid of advertisement period, you will have to deal with stuff like famous academic Op-Eds, celebrities recommending who to vote for, media bias, etc. So you can control the blatant intervention but at the end you have to trust all voting citizens are discerning adults, savvy consumers of information in a complex world, although you know that is not true.