I’m not sure what you’re talking about.

I own a Tesla Model 3 as my daily driver. Phantom breaking works exactly the way I described it. And it’s not hard to understand why: the intent of the system (like all other emergency braking systems on modern cars) is to avoid a collision with a perceived object in front of the car. A gentle regenerative slowdown wouldn’t even make sense in that scenario.

Phantom breaking behaves the way a human driver would if they were attempting to stop short of an impending front collision. It just so happens that the Tesla is happy to engage that behavior in all kinds of fun scenarios, like if somebody leans an inch into your lane, or a bridge has a shadow it doesn’t like, or it decides the potholes are a force field in front of your car.

we must have different highways. I've never had anything close to full braking. only slowing for disabled vehicles/highway barriers

or maybe you're using it off highway?

I’ve experienced it on highways, but as I noted in a parallel comment, if Tesla thinks Autosteer isn’t viable on non-highways, it’s odd that they make it available. They have no trouble identifying road type and using it to determine speed restrictions for autosteer, and no problem disabling autosteer if they can’t ID the lines.

Maybe the phantom breaking is so harsh in your car it’s giving you amnesia, because it’s a well-understood Tesla failure mode on the Teslamotors subreddit, TMC, and every other Tesla owner forum I’ve seen.