Perhaps you can try following some of the advice here, regarding android settings.
https://stackoverflow.com/questions/22450478/android-device-not-recognized-by-adbYou can make it a little easier to see if the device is detected without recompiling the game, by going in Stencyl to
File > Preferences > Features, and enable "Device Manager". Then every time you open Stencyl, and again every 30 seconds after that, it checks if there have been any changes to what devices you have connected.
If it sees the device, it'll print a message like this in the log viewer.
2020-02-26 13:07:19,813 INFO [AWT-EventQueue-0] stencyl.sw.platform.android.AndroidDeviceManager (AndroidDeviceManager.java:scanConnectedDevices:106): Found new device:
LGMV300Kf6761c6f
LGE LGM-V300K, SDK 28
If the device is seen
when Stencyl first starts, it'll also place an extra menu item in the
Run menu. (Not great, but that's why this is a beta feature).
Run > Android Device > (Device Name)
In my case, I could also see the device's files, but it wasn't until I changed the device from "file transfer" mode to "photo transfer" mode that it was able to be detected by adb.