RAX40 160mhz channel selection

Hi,

When set my 5ghz access point to a 160mhz channel (up to 2400mb/s) I can only chose between channel 36 - 64.

Though when I chose DFS channel 56, the router put me on channel 149.

I was getting great download speeds on this channel @160mhz.(~850mb/s on Iphone 11 near router and ~450mb/s wirelessly at my PC roughly 20ft. away.) both are wifi 6 wireless devices.

I had switched channels and experienced worse speeds so I decided to switch back to 56, though this time it actually used channel 56 and my speeds are not nearly as good and some devices will not conenct while using this channel. I also have greatly reduced range.

Why can I not manually select to us channel 149 (UNII-3) 160mhz?

Also when I configure my access point to a 80mhz wide channel (up to 1200mb/s) no matter what channel I use I can only get speeds of ~450mb/s download on the Iphone 11 near router and ~200 to 250mb/s download on the PC about 20ft away.

I get the best range on channels 149 and up.

When I do a speed test on my router for the wired connection I get 875mb/s download and 32mb/s upload. (I have 1GB/s download, 30mb/s upload service).