deleting cookies on close, with exceptios for sites, is a feature that is build into firefox, no need for an extension
if you use librewolf there even is a small toggle for keeping cookies so you don't have to visit the settings every time you want a new site to remember you
"Consent-O-Matic" or, if you don't care about whether cookies are refused or not and just want the stupid banners gone, "I still don't care about cookies"