I think this is your clue. My guess is that you participated in testing AI Video Search when it was available as a pilot program prior the availability of Cam Unlimited Pro. Since the launch of Cam Unlimited Pro, AI Video Search has been part of that product.
Yes, because it’s a feature of that subscription tier now.
As far as I know, the only way to do that now is by upgrading to Cam Unlimited Pro, because those who were trying AI Video Search prior to that subscription’s launch lost access when (or shortly after) it was introduced. You just discovered that a few days ago because you hadn’t tried searching since you lost access to that feature.