Seems like a dead end for now. While the files will be saved as ALAC don't think there is any BT option to pass lossless audio. Does any hardware iPhone, ATV, AirPods Max or Mac support Enhanced aptX BT? Or more likely will Apple make its own proprietary lossless codec, maybe a version of ALAC for a BT 6.x implementation (Sonly has LDAC)? This would likely take a couple of years.