Also, the stock Music player app does support Hi-Res. Looking at the Audio Detection Log, I can kind of tell why it is the only one that does...
20:35:45.601 v3-build-853-arm64-play
Device: SonyAudio Sony NW-A100Series icx1293_001 EVK [arm64-v8a, armeabi-v7a, armeabi]
FAILED to read=/vendor/etc/audio_output_policy.conf
FAILED to read=/vendor/etc/audio_io_policy.conf
FAILED to read=/system/etc/audio_policy.conf
FAILED to read=/vendor/etc/audio_policy.conf
USB can handle Hi-Res - sdk=28
FLAG_VARIANT_USB_ONLY
OK flags=0x404001400000000
FLAG_VARIANT_USB_ONLY
FLAG_SUPPORTS_USB
FLAG_SUPPORTS_FLT_DYN_RANGE
FLAG_SUPPORTS_LDAC
INTERNAL_OUTPUT_FLAG_SR_192K
INTERNAL_OUTPUT_FLAG_SR_176K
INTERNAL_OUTPUT_FLAG_SR_96K
INTERNAL_OUTPUT_FLAG_SR_88K
Requests for Hi-Res Support (please state which build of Poweramp you are using)
in Poweramp Feature Requests
Posted
Seconded.