To put your comments into perspective with the OP's question, a Model 3 owner on UK roads, what car spec and versions of hardware and software are you experiencing these issues on? Long time since (and only then briefly) I've been on an Australian motorway but do recall them being similar in standard to ours or New Zealand (which I have driven on many times) equivalents, so would expect the car to handle normal driving features in a safe and predictable way.
I've experienced aggressive swerves when negotiating (I soon learned what scenarios may caused problems so don't TACC/AP/NoA in them) on and off ramps and lane flares (single into multiple lanes) where car plays 'pick a lane, any lane, oh, it picked all 3' which I am not convinced isn't a LHD/RHD issue, but never had anything on a marked road with reasonable curves where I felt it was going to run me off the road.