What would the highest sample/bit rate I will see with my setup with Amazon Music?

I have my Arylic B50 connected to my computer using USB. (DAC mode)
Up2Stream USB Audio is selected in my audio settings.
Sony MX10003 Bluetooth headphones are connected to the Arylic B50.
When playing music on Amazon Music (ULTRA HD) for some tracks the audio is listed as follows:
Track Quality: 24 bit / 96khz
Device Capability: 24 bit / 48khz
Currently Playing At: 24 bit / 48khz
Codec: FLAC
My Up2Stream USB Audio has 16 bit / 48000 hz selected (DVD quality)

Should I believe Amazon Music? Or is the Up2Stream audio what I am hearing in the headphones via Bluetooth?

unfortunately the USB receiver in the unit will only do 16/48 max so no matter what you set the source to it will truncate it down to 16/48

that’s it.

the device is not HI-RES certified thru the usb, maybe it is thru the optical coaxial

Unfortunately, I returned the unit last week because I noted some other shortcomings that didn’t match how I wanted to use it.
It’s a nice little unit but it wasn’t for me.