Here’s my opinion…
A cumulative of 4 crappy power cords won’t make as much positive difference as one great power cable on your amp. So instead of buying 4 garbage power cables at $150 each, I would get the best possible power cord for the total you’re planning to spend and put it on the amplifier and wait to upgrade the rest later.
On a used market:
AQ Tornado or AQ Thunder (latest editions).
Older Shunyata Alpha Helix - Taipan or Python
TWL Seven Plus. Great bargain used and works awesome on the amp and leaves you some cash towards the next purchase.