DUDU7Dubai I might have a theory as why. I noticed Android doesn't seem to resample to 48kHz when using Bluetooth, but sends to BT with 44.1kHz (at least on my Samsung).
As Dudu staff said, BT, which is happily accepting 44.1kHz is connected via analogue to the mixer and dsp, so in theory the most horrible android resampling doesn't happen here, but "just" analogue to digital conversion in native 48kHz.
So, it might sound better (as android resample is famously known for treble harshness), yet it isn't anywhere near lossless quality. As of now, Spotify on any device (I think maybe except sonos as they teamed up at some point) cannot provide lossless. Is it better though than standard Spotify quality? It is, as it's not compressed. Is it economically sound? Absolutely not, as you're paying for lossless you're not getting.
I settled with Tidal using UAPP. Same is achieved with deezer. Via USB audio it's bit perfect. For convenience (maps and calls) I'm using spdif in 48kHz mode, uapp is resampling to it using internal resampler which sounds miles better than Android built in.
As I said before, I'm stunned why OP is looking for best audio quality, yet does triple AD/DA conversion. Madness.