BLE DIY solution with Audiolabs M-DAC

Hello everyone,
I am new to this forum. I hope I have posted this question in the correct fourm. I am hoping for some input on how to proceed with a solution I am working on.
Recently I have repaired an Audiolab M-DAC. I would like to add a BLE input. Preferably internal, with a cheap and small board. However external is However, I am uncertain what output would be the best option, either coaxial digital or SP/DIF? And would soldering the output internally instead of connecting externally be a solid choice to move forward?

Any advice on how to proceed?
I understand there may be too little info for good advice, so feel free to ask for any info needed!

Thank you in advance,
Do you have a particular BLE module in mind? Some of them only seem to have a analog outputs from their onboard dac. Maybe GPIO pins can export I2S or SPDIF, but not clear if programming information will be available for that.

Other than the above, there is pretty good thread in this section of the forum on bluetooth modules. Don't know if you have already looked at that?