@CumbriaChris
Hi,
Actually it should also say Archer AX12 on the box and the Archer AX12 router does support Wi-Fi 6. (basically that's what the "AX" stands for, because Wi-Fi 6 is also called 802.11ax)
Maybe try out another Wi-Fi analyzer for a crosscheck?
If the Amazon page for the article you ordered did not specifically mention "Archer AX12" anywhere, but instead specifically said "Archer AX1500", then you should contact Amazon, because the "Archer AX1500" is actually another router model.
Edit: Note that the Archer AX12 (as well as other AX1500-class models) only supports Wi-Fi 6 on the 5 GHz band, but not on the 2.4 GHz band.