Which  component should get the best power cable? I

I had a same issue. Suggest best cable be from wall to power bar but others may disagree.
I auditioned changing a SINGLE power cable from wall to an Ansuz8 D-level mains distro bar feeding a statement system (Raidho D5.1s thread by Ansuz D-TC cables throughout). I was skeptical at first about impact of power cables, but even to my cauliflower ears - just changing this one cable made a noticeable difference (for the money A-level cabs were ideal for me, but the D-level delivered the best sound overall). I have absolutely NO IDEA why changing this one cable (everything else the same) would, or even should, make a difference, but it did.

There is a thread you can read about this topic...it's here on cables topic...

It depends on your components. Start with the component that needs the most "help". For example, a mass market digital player is likely to need the most help.