OP: For me, autopilot was made considerably better/more reliable by downgrading from NoA to just "regular" auto-pilot.
Started with regular AP, very very rarely experience phantom braking. "Great! They've fixed it!", I thought... and dutifully upgraded to NoA/EAP. Same drive as always from London to Gloustershire and it was insanely bad - perhaps 5 or 6 incidents until I turned it off and drove manually the rest of the way. One concerning thing; even if I turned off the actual Navigate on Autopilot button during the drive, I was still getting bad driving.
Upon arrival, I immediately requested a refund. It went back to regular AP, and since... no phantom braking. I suspect EAP is using it's own stack, where as dumb Autopilot (no lane changes or anything) is a legacy stack. But, for me, dumb AP is usable... EAP is not.
Considering that NoA is more like DoA in the UK (see what I did there), if downgrading is an option... I'd recommend it.