BP50 optical/coax output Volume control/DSP-EQ/signal processing

Hi, I have a BP50 and I’m very happy with it so far, I’m using it with my TV through hdmi arc. I also use the parametric EQ to tune the sound to my liking. The rca output is connected to a pair of active speakers and the sound is already great.

I’m willing to make it sound even better and I’m thinking to connect the optical or coax output to a dac with a better dac chip (with more recent sabre or akm chip).

I understand that the bp50 outputs 48khz/16bits through optical/coax (based on website product specs).

Before buying a dac, I wanted your help to clarify few points:
1/ will the bp50 optical or coax output volume be adjustable with the hdmi arc cec? (as it is with the rca output)
2/ is the optical/coax output signal impacted by the bp50 dsp (EQ) adjustments? In other words can I benefit from EQ adjustments with the optical output?
3/ is the optical/coax output a pure digital signal (meaning that it remains digital from hdmi input all the way to optical/coax output and does not go through the bp50 ess9023 dac chip conversion)?

Would appreciate a reply from Arylic team or someone who knows/tried the same.

Thanks for your help!

Anyone from Arylic team who can help?

thanks