DAC for Gold Phantom (Stereo)

[ogs]

I'm afraid that will lead you into some difficulties. AFAIK there is no DAC, let alone MQA DAC, that re-digitizes (AD converts) its output so you can connect to the optical of Phantoms. You can of course connect a separate ADC to the output of a DAC, but this will be expensive if you want to keep the sound quality of the DAC - and a DA-AD-DA path is not recommended.
The best/simplest solution would be Roon which integrates nicely with Tidal and does (the most important) MQA first unfold before sending the stream out. If you are lucky Roon might use the optical on your PC so you wouldn't have to change your setup much.