Hi, thanks for your support, however I managed to finally get the app to output the correct format.
I did it by turning DVC off, turn off absolute volume for Bluetooth in developer options, disconnect then reconnect my headphones, and turning on DVC on Poweramp.
Now every track is outputted the correct way (using Hi-Res Output in Poweramp).
However another problem occured: when pausing music using Bluetooth controls or when changing the audio focus (like starting a video while listening to music) the audio would come out also from phone speakers. This affects every other app as well (so, let's say I listen to music using Poweramp and I watch a YouTube video, the audio would also come out from phone speakers).
I tried forcing speaker off using the app setting, but it will not work.
Anyways, Poweramp is saying that the output device is Bluetooth device.
The only way to solve this bug is by restarting the phone. Then anytime I use bt controls or the audio from another source starts playing while listening to music using Poweramp, i got the same problem over and over.
Is this also a problem related to my OS? Cause no other app that uses the hi res driver have such problem.
Thanks for your help.
The same thing happens when I disconnect only one earphone.