Test image for the Asus RT-AX89X: nss-edma-rework at ddf748baaef (EEE on the 2.5G and 10G ports, openwrt/openwrt#25754) plus EEE turned off on the internal link from the PPE to the QCA8337 switch (lan3-lan8).
ax89x-eee-diag.sh dumps the port, EEE, MAC and XPCS state:
sh ax89x-eee-diag.sh # dump
sh ax89x-eee-diag.sh off <port> # dump, EEE off on <port>, port state after 30 s
Use 10g-copper or switch (lan3-lan8) for <port>.