You are almost good to go. Change MQA Capabilities to Decoder and Renderer or just Renderer. With this first setting the Amethyst handles everything and with the second, Roon performs the first unfold. This is useful if you use any of Roon’s DSP settings. In both cases Roon passes MQA signalling to your DAC.
Note that you won’t see the DAC in Roon because you are using S/PDIF.
Your current settings are fine. Roon performs the first unfold (decode) and passes the MQA signalling to your DAC via the DigiOne. From then on, the DAC will do the final unfold or rendering. I use the Allo DigiOne; it’s a good transport and much better than simply using USB from a Raspberry Pi.
Here’s a good post that explains each of the MQA settings.