Which radio are you using to connect the iPhone to the network. In an AiMesh configuration, the AX11000 will use the 5G_2 radio as a backhaul channel and you may not be able to connect using it..
I have been playing with the AiMesh situation on my system. When I had the AX11000, the RT-AX68u worked fine as a node. But just to avoid confusion, could you verify the model numbers for your devices.. Is it AX1000 and RT68u.
Also, if you look at the AiMesh section in the firmware, what type of connection does it show, strong or weak?
Maximus Z890 Hero,
Intel Core Ultra 9 285K