Use a vpn with a Eu server. More sites like google will show a cookie popup with the “reject all cookies” option.
Reject all cookies if it exists. Otherwise accept cookies and then click on the :
shield icon > cookies and site data > delete (trash icon)
This is super useful when you want to read an article on some news website and it shows a cookie popup.
I use Waterfox which forgets all data on exit, with Privacy Badger and Port Authority extensions with no exclusions.
So far, no sites really “break”, if anything, they’re a little quicker… reading mode is nice to get passed paywall popups on most sites that want a subscribe.
If at work, I include the company-provided password manager for all my sites I need. Still works well (unless my post gets attention and companies try to break it)