Only thing that works for me

Akismet was worthless because it doesn’t block automated bots and once you’re on their lists they bury your site with them. I was up to 1000+ spam comments a day. That dropped to only 40 real comments (a few manually left spam, but easily controlled once the 960+ were blocked).

I do periodically change the random letters, numbers and characters any time I notice any spam coming in and that blocks them out again. Apparently, they can eventually crack that code no matter how long it is. But you can make them start over anytime you choose.