A simple first step to me would be to update the DMCA so that platforms using engagement-maximizing algorithms lose their section 230 protections.
If you're targeting individuals with specific content algorithmically, you're hardly a dumb platform for user-generated content, and I would argue that it's well over the line that would classify you as a publisher.
I really have no idea how we can define most of this esp using the framework of previously established law but I do think that a definition of Dark Patterns could be tangentially worked into the psychological make-up of gambling.
If you're targeting individuals with specific content algorithmically, you're hardly a dumb platform for user-generated content, and I would argue that it's well over the line that would classify you as a publisher.