A different line of reasoning (rather than telling you to simply change your components 'cuz changing components gets you into an infinite cycle!): before you buy, tweak!
Tell us, what is it about the Capitole Mk2 that you liked so much over your own system??
Does your digital front-end measure up at all in any way to the Capitole Mk2? If so, which attributes of your system do you like?
This should narrow down what you are trying to achieve + ensure that when you take the next step (tweak or buy) you will not destroy what you have but will build up.
The SFT-1 & MF A3-24 DAC are not the world's best system for sure (very few of us have that sort of gear) but I'm willing to wager that it can sound better in your system if you can tweak it & thereby squeeze out more performance from it.
Another reasonably priced DAC to consider is the Bel Canto DAC2. Good prices on used units here on Audiogon & very good sound - musical, tubey & extremely non-fatiguing. I've heard the DAC1.1 & am told that the DAC2 is more of everything that the DAC1.1 is.
Tell us a little more about power supply feeding these components, your rack, the type of floor, isolation of the digital front-end, any modifications done to the digital electronics & cables.
Sure, you can simply buy the Prima. Then tomorrow you'll hear the EMM Labs gear & want that. Then, you might hear the dCS or Goldmund gear & want that! So, where does this end?? Maybe YOU don't want it to end?