Following up: My truck updated on 11/24 to 39.5 (FSD v12.5.5.3) and it works like a champ. It makes so much difference! The upside is that it forced me to become comfortable driving Truck Norris. It'd been 30 years since I owned a truck.
Added later: I was on "Advanced Setting" and connected to wifi to get the update.
Is there any qualifiable information to suggest that “advance setting” allows a more seamless download? I get all the downloads without issue but always connected to wi-fi on the standard setting.