@XDA_EdgarPoe 

I see. Does the Canadian version of the X4860 router allow you to select Wi-Fi channels 120, 124 and 128 in the Avdanced Settings menu?

@XDA_EdgarPoe 

Thanks for sharing TP-Link's reply.

Since the Archer AX90 appears to be unique in the way that its 5G-1 radio does not support 160 MHz channel width by design and given the reply from TP-Link regarding 5G-2, this is clearly not good news for you.

If you don't feel like you can accept that situation, you should have a good chance of getting a full refund from Best Buy Canada if they indeed advertised the router supporting 160 MHz channel width (or 4804 Mbps data rate) for one of the 5 GHz radios.

Another (admittedly far-fetched) attempt could be to contact TP-Link and ask them if it's possible to change the channel assignment for the 5G-1 and 5G-2 radios in the Canadian version of the firmware. 
If 5G-1 was assigned channels 149, 153, 157, 161, 165 and 5G-2 was assigned channels 36, 40, 44, 48, 52(DFS), 56(DFS), 60(DFS), 64(DFS), then in theory the AX90 should be able to perform according to its specification even under Canadian regulations.
However, it could turn out that this scenario would have required separate output power calibrations for these frequency bands to be performed at the factory and the absence of the pertaining calibration data in the routers flash memory would rule out changing channel assignments via firmware update later on.

@XDA_EdgarPoe 

I doubt the AX90 would accept another region's firmware via the regular update method.

There may be other methods to flash such a non-authorized firmware, but there is a good chance the router won't work as expected afterwards or could even end up "bricked". 

@XDA_EdgarPoe 

That sounds promising. I wish you good luck!

@XDA_EdgarPoe 

Just bought this router as well today hoping to improve my network, but it feels like a step backwards.

I am having the same issues in the UK. Cannot get the 160Mhz to work at all. As soon as i set it to 160Mhz on the second 5Ghz band, that particular SSID is no longer available. I have to revert to 80Mhz for it to work again.

Also, my link speed on the router to the PC never goes past 1.2Gbps connection even if im sat next to the router.

On my Huawei AX3 Quad Core router, I can select 160Mhz and assign to any channel (Not limited like the AX90). My link speed is constantly above 1.7Gbps and if im in the same room as the router, 2.4Gbps.

Spent 3 hours on livechat with TP link only to end with a ticket being raised and no solution.

Speedwise, on the AX90 i get about 600Mbps (+- 50 Mbps)  down and 50 up. On the Huawei AX3, i get 800Mbps (+- 75 Mbps) and 50 up. I have a 1 gig internet connection.

Cost wise, TP Link AX90 £270, Huawei AX3 £35. Seems like you dont get what you pay for.....lol

First world problems!