Which Garmin products require an engineer at Garmin to account for general relativity? Lots of products have GPS, but they use an off the shelf mixed signal IC

Which Garmin products require an engineer at Garmin to account for general relativity? Lots of products have GPS, but they use an off the shelf mixed signal IC that contains all the hardware and software required to implement GPS. As an engineer, you just feed augmentation data from a web API and receive a text stream of NMEA messages from the IC. It's literally glue code. The required skill set is the same one required to hook up the Shopify API to a web store (ie. "Software Engineer")