1. OnePlus 6 (A6003) 2. OxygenOS 5.1.0 (Stock ROM) Android 9 3. Comes according to the Official website with Dirac HD Sound as well as Dirac Power Sound. The phones SoC supports bitrates up to 32 bit/384000 Hz natively as stated here. I also attached the audio_output_policy.conf below. audio_output_policy.conf
The OnePlus 3 alongside the OnePlus 3T should both support OpenSL HD Output.