I wonder if the Joy-Con drift issue is partially related to the controllers communicating wirelessly. Since I would assume that the Switch Lite controllers, since they are physically attached to the tablet, no wireless communication is being used to allow the controllers to communicate with the system, only wireless communications for the Switch Lite would be for internet and the amiibos.
When the joycon are attached to the Switch, aren't they communicating with the Switch via a physical connection? A lot of people who have the issue pretty much play exclusively in handheld mode.