The businesses using dark patterns are disproportionately large corporations. The ones that have trouble implementing a regulation which is airtight against corporate lawyer tricks are the small ones. That implies the obvious solution that you make the rules specific to the large corporations, e.g. ones with more than 1000 employees. But the rules typically aren't written to do that, and as long as that continues you're going to get resistance from the very large number of small businesses you're screwing.