Hi there,
Just FYI, except those mobile Apps you mentioned above, there is an App named “LightBlue” which is more reliable and universal for testing BLE functionalities. No matter how you build that BLE UART serial library from Workbench or cloud, you can verify if the UART service is successfully added or not by using this mobile App to connect the BLE device.
The Argon reset issue after disconnection is most likely fixed by this way: BLE Peripheral UART Streaming Assertion Failure.
Best regards,
Guohui