I should clarify that my budget is $20K for entire system. I anticipate that the budget for the Integrated amp at somewhere around $9-10k. Leaving me 10K for DAC, Speakers etc. I am am likely to buy some used components to be efficient with my monies.
With a $20k budget for the whole system you don't spend half on the amp, not if you want to be "efficient with my monies." What you do is more like $3k for a Raven Blackhawk, $3k to maybe $5k for Tekton Double Impacts or Moabs, and then you have a good $12k to $14k for your source, speaker cables, interconnects, and power cords.
That answers your question about which "devices" you're missing. Speaker cables, power cords, and interconnects are every bit as important as the amp. If you don't believe me, get a $12k Raven Reflection and a $3k Raven Blackhawk, use a $4k Synergistic Atmosphere Level III Euphoria interconnect on the Blackhawk and a patch cord on the Reflection. Your total cost with the Blackhawk/Synergistic will be less but sound better.
The exception would be if instead of a whole system one and done this really is just the starting point, you plan on spending the next 5 years or more patiently thoughtfully improving everything, and you would like to start off with a statement or Grail type amp as the centerpiece or anchor. In that case its the Raven Reflection, hands down, and for probably more like 20 years than just five.
That's a pretty good plan by the way. If that's what it is.