I have the new ASUS RT-AX88U that I am using as the main router. I bought 2 new RT-AC68U in the hopes of setting up the AiMesh, had many problems so decided to give up that idea. Now I am using the 2 AC68U's as media bridges. I noticed that when no devices, attached to the bridges, are working for a few hours, it drops the connection. I find this out when I start a device that is connected to the bridge. After a few minutes it automatically starts working again. I also have an old RT-AC68U that I am using as a repeater, for some reason that works fine. The repeater is connected to a bunch of IOT's that always stay on. My bridge problems are similar to the ones addressed here. I wanted to say this here to add additional info to the discussion with hopes that someone may have a solution.