rather than buying such cables specifically for each DSP, maybe buying/using a suitable quality mains block connected to a Shunyata (NR) mains cable is the better to improve all of my system’s components (not just my DSP’s).
I like your thinking.
I'd probably go for something other than Shunyata myself, but cleaning up the power and then distributing it makes good sense. You just have to make sure that (a) you are not choking the current anywhere and (b) nothing is polluting the power on the "clean" side.