> The UX of those dialogs is largely a dark pattern because the law did not demand implementation details, yet people blame GDPR because businesses designed them to be a nightmare to use.

IMO the law was clear enough as highlighted in the sibling comment. It is poor enforcement that's been a major issue. If a company registered in country A flouts GPDR, even in country B, there's nothing country B can do, other than delegate to country A's data protection / privacy authority. If country A then drags their feet and takes no action, we arrive at the current situation.