Wi-Fi or PLC?

[supaDean]

@tsmithpam  You won't need ethernet for streaming in Direct Optical, it is only needed to reach the web configuration UI on the speakers.
For volume control you'd have to use digital volume, like the one in Roon. Volume control in Phantoms is digital anyway so there is nothing to loose (maybe apart from convenience).
Instructions for Direct Optical on Phantom I https://help.devialet.com/hc/en-us/artic...M-I-CUSTOM

Correct. @tsmithpam I've implemented a preamp which controls volume with a remote. Also does digital room correction. I've written a ton about it in a couple different threads so I'd suggest you do some homework and read it.... this way you can learn how to tweak for your needs.