You have Consent o matic firefox extension which works quite well, it works well on most websites
I started to write this comment meaning to add that Firefox does it all by itself now, but I just read that such feature "is not currently available anymore".
https://support.mozilla.org/en-US/kb/cookie-banner-reduction
Does anyone know what happened after years of development, before I delve into their Bugzilla to find out?
So some websites actually require an accept/reject, and don't work if just visually hiding the banner, which is what this does.