Device Model: iBasso DX200 (DAP, not a phone).
ROM Version: Stock Android 8.1
Reason: Dual ESS9028Pro, I think the DACs definitely supports Hi-Res...
The OpenSL ES Hi-Res output only supports bluetooth and USB-DAC...There isn't such a file named audio_policy.conf either in /etc or /system/etc or /vendor/etc... I can only find a file called audio_policy_configuration.xml. hope it helps.
The DX200's default music player really sucks. Poweramp is way better. The only problem here is Hi-Hes output otherwise everything is perfect. So I