I believe that you need to seriously evaluate what your goals are. Come up with a strategy that works best for you. As this is a hobby, there are no wrong answers.
Do you want a system that is "good enough" as some would suggest?
There is nothing wrong with that if that is your goal, but I do not think it is as you seem to have made a committed investment in your electronic components.
You have also identified that power delivery to your electronic components is important. And you are right to believe so. Stock PCs will generally yield 50% (if that) performance out of your components, meaning that your units are not operating at the level they were designed to with stock PCs in place.
That said you have initially budgeted an average of $140+ for a possible upgraded delivery of power system for each one of those pieces of equipment. Based on the DAC alone - I am taking an average since you did not list the model, you are looking at a 5% investment
I doubt that you are going to make much of a difference with that kind of Budget. This is a step sideways rather than a step forward towards getting the maximum performance out of the components you have already invested in. Generally a 25 - 30% investment in power delivery is where you are going to realize substantial performance changes - in everything.
Think of your Power delivery as another Component to invest in. I would keep the stock PCs and start with a power distributor and then move methodically piece by piece. After the Distributor then make an investment by replacing the PC from the wall to the distributor. Next move to the DAC, Monoblocks and Speakers. You will be able to source out PCs with a better architecture and get the best return on your investment.
Also check out
https://www.analysis-plus.com/
For those that Care: Over the years I have been lucky enough to be invited to a few listening rooms from top Component Manufacturers.
Not one of them use Stock PCs.
