Which of these power cords ?

You're not gonna get a straight answer on this topic around here, or anywhere for that matter. Buy a couple of those inexpensive ones you mentioned and see yourself. Hopefully you can return them if not satisfied.

Given your goals and short of making your own cords, which you should seriously consider, I think your best bang for the buck will be Cullen cables. On paper it looks like the Red Copper cable is a great value at $99/6ft, but if you can swing it there’s a lot more built into their Crossover cable at $199/6ft. These two cables seem to be more neutrally voiced, but if you’re looking for a little more warmth in your system the Gold series cable is $129/6ft. Cullen cables get great customer feedback and the prices are tough to beat. Hard to imagine you not getting a significant benefit from switching stock cords to these.

As a a dark horse option, I recently heard of Raven Audio that also seems to make high-value cables. Their Soniquil power cable is $169/6ft. and comes with Rhodium-plated connectors that you’d need to step up to the $199 Cullen Crossover to get. There’s obviously a lot more to it than the plugs, but to me it indicates good value and may also be worth a try as you never know which cable will synergize with your system and tastes. And both offer trial periods, so you can try both with little/no risk. That’s what I’d do. Anyway, hope this helps, and best of luck.

Why not contact the Cable company to try a few power cables and decide for yourself. They charge you 5% plus shipping. If you purchase anything from them your 5% is applied to the purchase.

I also decided to dip my toes into the aftermarket power cord market and needed a large number of cords.  Not knowing what to expect in general I didn't want to spend too much.  At the suggestion of an Audiogon member I purchased these low cost cables at $50 per 6 foot cord.  They certainly SEEM well made (in China).
https://www.amazon.com/WAudio-Hi-End-Audio-Power-Cable/dp/B01L2UNMXI/ref=sr_1_6?keywords=audio+power...

These are my first venture into power cords and they make a positive difference in my system.

It is my understanding that you would generally use a different gauge wire for power amps than for your digital gear.  If you go with more expensive cables this can make a fairly large cost difference as the higher gauge (thinner) cables generally are less expensive.