I just got a new RE705X range extender because of the 160 MHz channel width for increased speeds. I'm using this range extender on a OneMesh network with a tri-band Archer AX90 router. This router has a 2.4 Ghz at 40 mhz channel width, a 5 Ghz-1 at 80 MHz channel width, and a 5 Ghz-2 at 160 MHz channel width.
The RE705x seems to only latch on to the 2.4 Ghz and 5 Ghz-1 at 80 MHz, and will not use the second 5Ghz channel. If I turn off OneMesh, and I turn off 5 Ghz-1 on the router, then the RE705x will use the 5 ghz-2, and the RE705X will also broadcast in 160 MHz channel width. But as soon as I turn on OneMesh (which requires enabling the routers 5 Ghz-1), the range extender goes back to the 5 ghz-1 with 80 MH channel width, and slower speeds.
The settings for OneMesh are relatively locked down, so I'm not seeing any way to force the 160 MHz option on the range extender. Is there a setting I'm missing? Will it be addressed in a future firmware update?