Tech9
Part of the Furniture
if the things one uses are working
This is correct. One of the reasons most folks don't see the bugs in firmware and report "no issues whatsoever" 15min after upgrade.
It may not be a good idea to turn off this option at 5GHz
It applies to g/a devices only. There is nothing in technology supporting change in ac/ax behavior, unless it's another bug in Asuswrt.
It's part of the 802.11ac wave 2 standard
It does more harm than good (reducing the overall performance) in a home environment with small number of moving clients around.