You've now completely shifted from "unusual behavior is sufficient justification to detain someone and this is necessary for 99% of real traffic stops" to "the police can usually come up with probable cause if they want."
Which I completely agree with. But that's a very different statement.
If a cop saw someone hiding in my bushes at 2AM, that strikes me as reason to think that the person is trespassing if not worse, and would thus justify a further look. It would not be done solely on the basis of "unusual behavior."
Shifted? Not at all. Merely articulated the specific mechanisms.
As you note - my original point stands, and is correct.
It’s difficult to come up with ‘weird’ or ‘suspicious’ behavior that isn’t going to be reasonable suspicion of something, and that is by design.
Or we could just go to disturbing the peace or loitering eh?