I can't thank all of you enough for this great advice.
This is great!
Based on everything you mentioned right now I am leaning towards my initial impulse of starting with a better dac and implementing the other upgrades over time,
I like the idea of integration but only to a point- as appealing as a single box solution may be I'd rather retain the ability to upgrade single components . That said, I would probably opt for a dac with a bridge/network Roon endpoint- I was thinking of a Bricasti M3 or maybe an M1 SE (really stretching budget here); another audiophile I know well swears by the Manhattan II. I believe any of these these should be a good step-up from the Moon 280D (though it remains a very competent dac).
The other option of course is a dac without any network card (maybe Aqua La Scala or Holo May) and investing in a separate Roon endpoint- Sonore etc as discussed above. In other words, spending less on the dac itself and to give more room to an endpoint upgrade. At this stage I'd probably leave the Mac Mini for last in the upgrade process.
In all of this I should mention what I am looking for; first and foremost I would like to eliminate that electronic hash that bothers me, and second I'd focus on a believable soundstage. Many often refer to soundstage width as an essential element but given the choice I tend to care more about depth,. And as I have experienced with analog when properly set-up, that sense of space goes hand in hand with "forgetting" about the speakers and all the equipment upstream. For this I can also forfeit some microdynamics for a better sense of the overall musical event (I sound like an analog person! but don't want to go overboard either as I do care about transparency, detail...and dynamics).