If in the US, "OpenWrt WiFi 6" options are largely the Linksys/Belkin E8450/RT3200, the TPLink EAP615 In Wall, the Unifi U6 Lite, and U6 LR. Both U6s and the Belkin/Linksys units are AX on 5GHz spectrum, and N on 2.4GHz. TPLink's EAP615 is AX on both.
Amazon US has it shipped and sold by Amazon as the first search result, at $150.
The Belkin can be found for ~<$100 on Walmart.com, shipped and sold by Walmart.
I was unable to find the the opposite combination.
That being said, I think I should have listed it as:
Linksys E8450 and Belkin RT3200. Only difference is the Linksys is black and the Belkin is white. Internal HW is (so far) identical.
