This may not be appropriate for your use case, but have you tried rotating the publicly facing email address when you get spam or on an interval? For example [email protected] ([email protected], [email protected], …).

I believe most legitimate visitors send an email shortly after visiting a page with the address while spam emails often have a much longer lead time for new addresses (it takes time to get scraped, put in a database, and then get used).

However this does mean that extended communication on that address and saved addresses will not work well.