???
All router does the 36-48 and 149-161 for regulatory reason. U-NII-1 +U-NII-3.
IT's possible marketer cheat with the term 3bands, but it remain that DFS spectrum is a third band ( channel 52 to 144). Here the resume for Canada, pretty close to us.
The source is an expert:
source...
Then if you an expert, here the FCC link:
https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm?switch=P&id=27155
Maybe their in your conspiracy like wikipedia :) !
5.3 to 5.7 GHz exist, it's the third band. Look at the fact in the wikipedia article !
DFS channels are only available to those router who scan for a radar presence.
Tri-band router already exist ! I suggest you read about the DFS channels:
https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_or_5.8_GHz_(802.11a/h/j/n/ac/ax)
They are alreadly approuved:
https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_or_5.8_GHz_(802.11a/h/j/n/ac/ax)
Don't mix Wifi6E and Tri-band, they are 2 different things.
802.11AC does not exist on 2.4 GHz. When using your old router on 2.5 GHz woud were using compatibility in 802.11n.
802.11ax deos work on 2.4GHz and 5.x GHz. Did you use a 20MHz channel in your test ?
They are now certified WIFI6: https://www.wi-fi.org/product-finder-results?sort_by=certified&sort_order=desc&categories=6&capabilities=17
I don't know why they are so expensive ?!