> […] I've already toyed with using AI models to analyze browsers' screenshots and determining if it's likely phishing or not and it works very well.

Assuming the AI is comparing screenshots of real versus phishing, it can only figure it out for poorly done phishing websites.

As phishing scams get more sophisticated with scam websites that look exactly like the real ones, the only things that truly matter are protocols (i.e., HTTP versus HTTPS), domains, URL’s, certificates, etc.