[LinuxBender]

Anecdotally I moved some really old domains to fastmail and set the spam global rules to move anything with a spam score of 4+ to the spam folder and to delete anything 10+ and I receive no spam. This is not enabled by default. One of the domains I moved had several email addresses that had been leaked to the worst of the worst spammers.

For the sites that are not technically spam because I signed up for them, I have rules that move their emails to a folder and mark them as read. One can set retention of each folder. So if I realize I might have needed to view one of the emails, I can look for it but if I don't then it eventually goes away without bothering me.