Several weeks ago I wake up and internet is 'no access. Almost all of the Alexa devises were offline as well as my Ring cameras and smart phones. I had to restart the router to get it working again. Wired devices seem to be ok for the most part. This happens almost every day. The firmware is up to date. The router is not is the best locations (one side of the house) but the device that loose the connection are very close to the router. I have the 2.5 and 5 ghz separated into to different wireless names. Are there setting that are casing the drops?
Update, I also have a Asus RT-AC68P as the mesh, it has 13 of those 39 clients connected to it. so realistically I only have 26 clients on the RT-AX58U
