The problem we currently have with cookie banners is thanks to the browser vendors not caring about it.
An API could exist which a page can query, where the user has already pre-selected how they want to deal with cookies. For example reject all but the essential ones, reject none at all, reject some, according to certain criteria.
Even more, the browser could check if the page is adhering to the user's expectations, and if it doesn't, block it for a period of time, like a week or a month, and publish the fact that they ignored the user's wishes.
Possibly also give the user a signed document which claims that this page did not respect the user's privacy expectations, so that the user can use it in court.
These should be solvable problems.