There are actually cosmetic filter lists for removing such elements from the page. For uBlock Origin, go to the Dashboard, Filter lists tab, and look at the An

There are actually cosmetic filter lists for removing such elements from the page. For uBlock Origin, go to the Dashboard, Filter lists tab, and look at the Annoyances lists. Both Fanboy’s Annoyances and EasyList Cookie include ##.js-consent-banner, which deals with Stack Overflow’s huge obnoxious banner.