Try this–think about it in terms of goals, instead of use cases.
In general, Roon’s goal is to make sure that MQA files are decoded whenever possible.
If Roon thinks your DAC can decode, then it’s going to skip software decoder whenever practical, but engage it if you have configured DSP in Roon (this is because DSP must happen post-decode–this is just how MQA+DSP work together).
If Roon thinks your DAC has rendering capabilities, then it will:
- Ensure that the software decoder produces rendering instructions (assuming we are core decoding in software at all)
- Preserve the rendering instructions prior to any DSP performed in Roon
- Restore the rendering instructions after any DSP performed in Roon
- Disengage Roon’s upsampling when playing MQA content, since this would make it impossible to restore rendering instructions.
It sounds like your goal is to make sure that software decoding is turned off whenever possible. Roon is already designed to do that, because that is the correct behavior for playing MQA. You don’t need to use advanced settings to get that outcome.
The mental model wherein you worry about DSP+Room correction disrupting the stream is outdated. There are MQA-sanctioned ways for applying DSP to MQA streams, and Roon has implemented them. If you want to use DSP, use DSP. If you want to be bit-perfect, turn off the DSP.
The second setting–Enable MQA Core Decoder–is a way to make sure that the core decoder never runs no matter what. The problem with turning that switch off in your situation is that if you turn on DSP, you’ll end up with worse sound quality than if you had just left the settings alone.