HifiBerry Digi+ Pro vs. DAC+ DSP with Devialet Phantoms

Maybe someone can help shed some light on this for me, as I’m arguably rather clueless here :relaxed:

I’m currently using a HifiBerry Digi+ Pro as a Ropieee endpoint for my two Gold Phantoms in “Optical Direct” mode connected via TOSLINK. One of the downsides of this setup is that I need to use DSP volume in Roon to control how loud they play.

Now that I’ve read about the HifiBerry DAC+ DSP I’m wondering if it would be beneficial at all to use its optical TOSLINK output instead and rely on the onboard DSP to do the volume adjustment. Would that do anything at all to the sound and/or turn the stream above from “High Quality” into “Lossless”?