Continued MailSploit spam getting through in 2020?

For the past two weeks I have seen a steady and persistent flow of clearly SPAM emails with dubious links, possibly phishing or malware. The MailSpoit shows mals coming from all sorts of what should be valid sources, but the senders use the Subject: =?utf-8?b? to cheat around the old mail RFC. Shouldn't COX be above and ahead of this sort of noise?