Some can be modified to output is audio, I did this with a CSR64215 board,
Bluesuite software,
BlueMagic, atxs0108E shifter to talk to the 1.8v logic, and dump the SPI flash using a ch341.
It was a PITA, these modules are extremely easy to brick, so the SPI flash backup is a must.
I mainly used it to fix distortion, the soc EQ had +6dB amplification, causes the output to clip over 60% volume.
While doing so I tried interfacing a PCM5102A I2S DAC, it worked, and that was all, I reverted to analog output.
Then Qualcomm bought CSR (Cambridge Silicon Radio), renames the devices to QCxxxx, made all the docs and tools pretty NDA, though you might still find them.
Search for I2S bluetooth receiver, for sure you'll find something