“In most cases, the add-on just blocks or hides cookie related pop-ups. When it’s needed for the website to work properly, it will automatically accept the cookie policy for you (sometimes it will accept all and sometimes only necessary cookie categories, depending on what’s easier to do). It doesn’t delete cookies.”
Jerboa. It lacks some features, but it’s the official app and it’s also pretty minimalistic with its material you UI. Other than that Thunder is pretty good. They’re both FOSS.