I have One Mesh extender. I want it to connect Archer AX1800 DSL router. I enabled Mesh in the router settings. I tried to scan and tried WPS but neither method can discover the extender. The router specs saying it supports one mesh.

However after few minutes the extender connected but it now has_EXT suffix on its own ssid. How can I make it work as a mesh? Ie with same ssid so I don't need to switch it manually?