Your AVR is fine. You do not need a special DAC. You likely do not need a power conditioner. --- Some people have claimed that one of their biggest SQ upgrades came from swapping out an AV receiver for a pure pre-amp.
I will address this in a slightly different manner.
Your receiver, like mine, is very good and above average in quality. The likelihood of easily finding better in an affordable price bracket is going to be a daunting task.
Remember that at this level, our gear is likely as close to neutral as it can get. Moreover, there is not much evidence in my limited experience that Separates perform better.
If you want to chase electronic upgrades, then you are going to be getting into the realm of spending multiples of what you have already, and not just 2x... but 5- or 10x. Many of those possibilities may very well still leave you scratching your head in a DBT. So tread cautiously.
In terms of sound quality, it is now, and will forever be
your speakers. I'm not interested in arguing this. How your speakers perform on there own, and in your room is SQ.
Room treatments can be necessary at times, but I think are often overused and applied with little reasoning. I would encourage you to make your room livable first. Decorate it and get a good pad and area rug down in front of your speakers.
Then learn how to take room measurements. Tighten up your speaker placement.
Then figure out if you need to pursue treatments.
Take time to read and learn more, too! The Master Handbook of Acoustics and Sound Reproduction are great books. Read a book about introductory speaker design just to better understand what's at play in the whole system of the loudspeaker as a whole.
I do think you are on the right path,
@Landmonster , but without getting your system finalized for another few months, talking about things like DACs and replacing your binding post jumpers is foolish.
Enjoy what you have now, and get your Subs as soon as you can. Learn how to get them integrated into a good sounding system, then take stock of your situation!
Cheers!