Is a suitable solution to require visitors to fill out intent for why they came, and align that with your approved lists of supported intents, AND quiz them on some personal insider knowledge that only reasonable past visitors or new visitors who heard of you would have?

Like the credibility social proof of an introduction of a person into a social group. "Here's John, he likes Cats. I know him from School."

The filtering algorithm asks "Who who are you?" -> "What is your intent?" -> "How did you hear about me?" and stops visitors from proceeding until answered. The additional validation steps might kick away visitors but it also might protect you from spammers if you throw a minimally frictional challenge. Use cookies to not require this on every visit. Most LLMs would have the knowledge required to pass & for scrapers it's more costly to acquire this for a site than pay 128mb of ram to pass the Anubis approach.