Why do I need to connect with a USB connection first when my non-root phone is connected via Wi-Fi?
Because the non-root phone can't start the phone’s low-level program through the phone itself, it needs to be connected once through USB, and the bottom-end program of the phone is started by using the PC client. Once the startup is successful, the underlying program of the phone will always run without being shut down or restarted. Therefore, you don't need to restart the underlying program in the future; when the phone has Root, the phone itself can start the underlying program of the phone, so there is no need to connect USB to start the underlying program