Sorting out your grounding and cable routing can also make a big difference. I think this is part of what people experience as improvement when they start exploring power cables. A high quality power strip that does no filtering, is entirely passive, and employs star grounding and good quality parts can make a really nice difference.
I've usually found that amps should go directly into the wall, but other gear can benefit from some of the power filtering products (some, definitely not all).
I think power cords can make a big difference, for better and for worse. I don't understand why.
Putting in a dedicated 70A line using #4 to a new sub panel with three dedicated #10 runs less than 10 feet from the panel, furutrch outlets, and organizing my gear so amps are on circuit 1, pre and dac on circuit 2, and streamer/lps/clock/etherregen on circuit 3. The before was everything on one line that was a shared 50A circuit with my dryer. Even comparing to when the dryer was off, massive improvement, more than any power cord by far. But power cords still matter with these improvements. I suspect the right power conditioner could improve things, just a lot smaller impact than before.
Here I can sort of reason that the new sub panel and separate circuits separate the gear on these circuits differently from being on the same circuit because the high inductance of the circuit breakers acts as a barrier between them, even though they are all connected to the same 70A circuit. Then there's another barrier to the rest of the house at the 70A breaker, and another between the house and the neighborhood at the 200A breaker.
But why the power cord matters as much as it seems to is much more mysterious to me. Like lots of things in audio.
but I won't buy a specialist cable unless there is a plausible explanation for why it might be worthwhile