Hi@NTC25,

Thank you for contacting our community.

Do you want to create Ethernet backhaul between Archer AX73 and Archer AX23? Please note that your current network backhaul is still wireless backhaul. It is recommended that you can reset the Archer AX23 and then create Ethernet backhaul as below: How to Build an Ethernet Backhaul Using Two EasyMesh Routers

If you want to create a wireless backhaul between these two routers, please refer to How to add a router to an EasyMesh network as a satellite device

On the main router, does the 5Ghz work? Or did you enable smart connect on the wireless settings? Please confirm the 5Ghz is working normally.

If it works, you can try to change channel of 5Ghz to different channels: Changing Channel and Channel Width on a TP-Link Router (new logo)