The answer usually comes down to one question: what was the driver doing on the app? Rideshare insurance is layered, and which policy applies depends on whether the driver was offline, logged in and waiting for a request, or actively en route or carrying a passenger.
When the app was off, the driver is treated as an ordinary motorist and their personal insurance applies. While they were waiting for a request, a smaller contingent policy from the rideshare company may apply. Once a ride is accepted and while a passenger is aboard, the rideshare company's larger commercial policy typically applies.
That is why establishing the driver's app status is one of the first and most important steps in a rideshare claim — it can change which insurer is responsible and how much coverage is available. Saving your trip records and preserving the company's data early both help.