Trying to setup TiviMate on newest Onn 4k Streaming Box for External USB

I have searched but not found a fix to this specific problem. I have the new ONN Streaming 4K box. Installed TiviMate and watched the videos on setting up an external USB drive. Including the one using XPLORE file manager. But it will not let me grant permissions to access/write to the external drive.

The popup in XPLORE that should allow me a “one time action” to grant permission - gives me an error stating “You Don’t Have An App That Can Do This.”

I have also tried formatting it in the ONN system to both “use for external storage” as well as the format for use as the ONN storage mode. Seems to make no difference for this. XPLORE lets me create the TIVIMATE folder, but then won’t let me have permissions to access it. And in TIVIMATE you go to select the folder (which it sees), but it gives a “failed to change recordings folder location” error.

I have tried both enabling and disabling USB Debugging. I have set USB to MTB transfer mode (while in USB Debugging mode, as that is the only time it lets me change it from “charging” mode). I am at a loss.

Any help would be greatly appreciated. - Thanks.