What about blacklisting companies that post the same links from their ATS platforms for months at a time? It may be difficult to track from an admin perspective but as an applicant that has been browsing this for a few months, a lot of these are easy to filter out
I can show examples from this current / latest monthly postings
I don't know what a ATS platform is, but there are some companies which are nearly always hiring, so the appearance of a job post each month isn't dispositive.