I notice it might possible to get the wan port working at a lan port by using older image of openwrt's ax53u image because the device tree of the older image of openwrt's ax53u's drive tree r missconfiged to have 4 x lan n 1 x wan
(yes i know i could rebuild the kernel that have the device tree that configed to have 4xlan 1xwan)
EDIT : I rebuilded the kernel and made openwrt to support it. (see OpenWrt support for Asus AX1800HP)