Here is the cheapest WiFi 6 router https://www.amazon.com/Jlink-WiFi-Router-Wireless-Computer-Router/dp/B09YH69WN5/
Price: $29.99, 40% off -$6.00, 20% coupon Tax $1.86 Total: $25.85
Based on MediaTek chipset, FCC page https://fccid.io/2ATGV-UNR030Z
Not in the TOH ?
The SoC isn't supported in OpenWrt. "ZTE ZX279128R ARM Cortex-A9 dual-core, 1GHz" The cheapest WiFi 6 router is still Asus RT-AX1800U which is RT-AX53U under a different name, and might be cheaper in some places.
Bellini RT1800 might be an option.
If u r luckly enough u might find a seound hand ax1800HP for 180HKD (22.94USD)
None of the RT-AX54 clones are sold here yet. RT-AX1800U is the cheapest.