Power cord - 5 ft vs 10 ft ?

as short as possible.  as long as necessary for comfortable routing.  Avoid coils and loops.  

these are rules of thumb that are based on physics.  that said. you probably won't hear a differnce between 5' and 10' if both are good quality heavy gauge (10 awg) cable.

It's not length son that's important, it's girth.

Shorter if possible. Same thing with interconnects.

Some will say short, some will say long. Some of the Jason Bourne ilk will say it does not matter, like usual. These strange dudes don’t think cables do anything, but for some reason post non-stop in all cable related threads 🤔

Move closer to the power company's generators.