> What would steelmaning EU regs have looked like?

A simple "decline [all]" / "accept" choice, not a huge list with dozens of sliders for dozens of options each labelled "legitimate interest" all of which are set to "Accept" by default?

Only use cookies to provide services that the user specifically asks you to provide. Never use the cookies to anything where the action wasn't initiated by the user. That way, nothing you do requires asking for consent and you don't need a stupid banner.

A header to opt in instead of a banner...

I'm sorry now I'm confused. Is UI design this hard? Is this neurotypical?

Yes, stupid shit like punishing your users with abusive UI for regulations you dislike is neurotypical.