I’m using a 4iiii single crank power meter with the Android mobile app and comparing it against a correct power display, Xert seems to be around double the correct power. I’ve also tried using my Kickr Snap as the power source and that seems to be the same. There are a number of other issues around the bluetooth connectivity, at times the config constantly changed to swimming even though it had previously been set to cycling, At other times power doesn’t display at all even though the config is showing everything enabled and connected. Uninstalling the app and reinstalling seems to be the only way to re-establish the power reading, however it is still reading double the correct figure!
Try using ANT. It resolves much of the Bluetooth specific idiosyncrasies with each power meter and trainer. All you need is an ANT+ stick and USB OTG Cable adapter.
Thanks Armando, unfortunately my phone no longer works with Ant+ since the OnePlus 3T was updated to Oreo, both native support and OTG. It’s been over a month and they still haven’t released a fix. Assume there is no way to resolve the BLE power issue?