I admit 'FSD' or 'Enhanced Autopilot' (I guess, I have FSD) has basically been 95% (success rate) of changing lane left to right and 30%
30%??? Seriously if you are getting less than 90% success on a wide range of roads (that meet the specifications the system is designed for) I would be booking a service call.
Certainly if you are using it on the same roads repeatedly where you know there's an issue and/or where it's not designed to operate with the versions we have here, then I could understand such a bad result.
For the CBR - BNE - CBR and CBR -SYD - CBR routes I do, I've never had a lane change issue apart from some user error generated ones in an older M3 with stalks on my first drive using the system.
Same with using it on major roads around Canberra.
For the whole lap of CBR MEL ADL CBR the only time I experienced the issue was the right to left a couple times only on the Hume heading south from CBR (and the reason for those became very obvious looking at the camber of the road, so I would avoid trying it in those sections in future)
The only other issue with lane changes that whole trip was single undivided passing lanes which I discovered is a limitation imposed here but it doesn't even attempt those just tells you auto lane change unavailable.
I would put the success rate based on wide ranges of roads where the system is designed to operate at close to 100% for left to right and 98% right to left.
Remember that the versions we are using here are light years behind what you might see operating in the US. For that reason I'd be very careful using it on areas it is not designed to be used here. We don't have anything close to the 'go anywhere and handle almost any situation' software here.