The high-level information I had in mind includes GNSS coordinates, the accuracy of those coordinates, and a separate flag that would indicate whether the GNSS has used certain correction information or whether, considering everything comprehensively, it can be judged to be reliable. In other words, does this mean that there is no separate flag and that accuracy alone must be used to determine precision?

The phrase "There is no API to get lower level information" means that no information used at the lower level is provided. I had simply understood lower level information to mean satellite pseudo signals or satellite signals.