Following instructions are provided without any warranty, and may even get you in trouble legally. The instructions are provided for testing, learning, preventing e-waste, and should be use with care. We (including contributers + commentators) are not responsible for any damage to your device(s) or any legal issues.
Instructions have been moved to https://github.com/francoism90/asus-router. :)

@Linden1
You can do it via NVRAM or via
wlYou may need to select a different interface number, e.g.,
eth6or so... On my AXE11000 I configured it like this:Then
NOTE! You also need a client supporting those channels. With Intel's adapter with theri stupid LAR, I had no chance!! I replaced my Intel AX-210 with Mediatek MT7922. It works under Win10 and Ubuntu: