Bluetooth? No, haven't tested these. But then you're testing Bluetooth codecs, and bluetooth implementation, not just the DAC.
Of course I am, see also my recent replies for Geert. This is about real products in the real world, who cares about "just the DAC"? That would be a purely academic discussion, especially in recent years with manufacturers having started building these more complex "DAC" chips that are really integrated DACs and headphone amps (DAC-amps-on-chip? DAOCs? DAC-amp-systems-on-chip? DASoCs?

). I think some people have not woken up to this little complication, which makes it so you can no longer support the same statements you could before about "the DAC chip", since today "the DAC chip" also contains a headphone amp section.
I wanted to see if I could clarify the recording setup issue, so I put the same song through the HiBy FC3:
Even though it's a much cleaner DAC/amp, I have to admit there may be larger distortions due to the recording gear than I thought, since I'm seeing those weird sub-bass lines again, going through the whole song. I should probably always compare device vs. device so that those errors are subtracted out; device vs. file seems to be messed up too much by the motherboard line-in's defects.
Also, on deeper thought, the shades going up across the whole spectrum when the song goes quieter are probably just a natural consequence of calculating a delta vs. quieter original content: even if the errors are staying the same in absolute value, they're now higher dB vs. the barely-there content. So those probably mean nothing as well. *sigh*