Thanks for your reply.
I have all the 3 settings disabled. As long as WASAPI is used in non-exclusive mode every soundcard or DAC is opened with its default system settings, whereas in the exclusive mode app which opens the DAC can set them.
So as a workaround I have started playback, checked sampling rate, stopped, changed Windows default sampling rate for my DAC to match the sample rate of my audio files. The sound improved a lot.
Unfortunately this workaround is really inconvenient, especially in a longer run.

Could you add WASAPI in exclusive mode? It could be marked as unstable etc.

Do you mean VLC as a standalone app? I haven't spotted "exclusive" mode there for WASAPI.

I believe it is caused by not using WASAPI's exclusive mode. Wouldn't it be easy to add it? GStreamer wasapisink() function needs exclusive mode flag to be set (if this is indeed the function being used to output audio).

I am running Strawberry 1.0.17 on Windows 10. It downsamples all high resolution files. No matter of the source - streaming nor local file. No matter WASAPI nor DirectSound.
For example if I play local FLAC file 24/96 control panel of my USB DAC shows the DAC was open at 44.1kHz only.

I know GStreamer has hi-res support. What about Strawberry? Is it lacking? Or there's a bug?