Any luck with other output methods?
The audio output menus at first can seam a little convoluted. You'll see a list of the output methods (opensl, audiotrack, hi-res, aaudio, and chromecast). Whichever method you select, you then see a list of all the output devices, with toggle switches and a settings gear next to each. Clicking the settings gear gets you to where you can set (or have Poweramp define) the output bit depth and sample rate.
At the moment, you don't have any forced resampling happening, which for 44.1 kHz content is a good sign. If you were stuck to using opensl output (which hopefully you won't have to be), from the screenshots alone I don't see any settings that would cause issue just yet.