If I am interpreting your needs correctly… there have been a few topics on similar attempts… tricky it is 
Search this forum for keywords like Serial Terminal, Debug, etc.
I managed to follow in a developers footprints and send debug serial (Blynk Debug) to LCD & OLED displays… that same technique can be used to send the data to the App’s terminal… but not any good for troubleshooting since if the device is not connected in the first place, then… well… no terminal action 