I implemented all of this in hCaptcha 6 years ago, not just to distinguish bot from human but also to recognize the keyboard/mouse behavior of the same person signing up for many accounts or testing multiple credit cards. This kind of abuse detection was a part of Cloudflare when they switched to hCaptcha in 2020 and I had thought they already implemented all this themselves four years ago when they transitioned away from hCaptcha in 2022.

Didn't recaptcha v3 also do this? iirc the "silently monitor in the background" was part of the selling point.