We used to get hundreds a day, but switching to a better ISP helped a lot- the cable company does pretty good filtering, and you can forward offensive emails, which they will block.
Also use 0spam ( zero spam ) which for a few dollars a month does further filtering and allows whitelisting and blacklisting of specific names or whole domains.
Sounds like you have good programs.
Changing ISPs does help for awhile.
Training the Junk Mail to
fetch the junk mail has really helped.
Oh, well, I see I am not having fun.
My husband has one of his Christian boards hacked and 1 of my little boards got flooded with posts.
Honestly, these sinners need saving.
Why do they pick on us little people?