Timer for on/off Android support

I’ve found this to be a great idea as I often fall asleep listening to something via YouTube Vanced, which sometimes out of nowhere tends to give very high CPU load and drain battery.

So I made a very simple app that has a slider to select timeout in minutes and then a singleshot QTimer which on timeout makes the following call via DBus:

QDBusMessage mm = QDBusMessage::createMethodCall("com.jolla.apkd",
                                                    "/com/jolla/apkd",
                                                    "com.jolla.apkd",
                                                    "controlService");
mm << false;

QDBusConnection::systemBus().call(mm);

It works perfectly fine, but only if I disable sandboxing in .desktop file using

 Sandboxing=Disabled

Does anyone know what to do (e.g. which permissions to use, or whatever else needs to be done) to make it work with sandboxing enabled?