Try changing the WIFI setting to use a different specific WIFI channel as you may have some unrelated device causing interference such as home automation, security system, weather station, or...

Is your router working okay for other devices? You will get a connection with a router but no data if the router is not getting any signal from the modem. If other devices are working, power cycle...

The old router may be using a different WIFI channel and you are having some type of interference on the new routers selected channel. Go in your settings and select a different channel. Also small...

Interesting... I checked my Archer C8 and noted that the prefix for all of my SSID MACs including guest networks are prefixed "c4:e9:84" which is assigned to TP-Link. I could not see the hidden SSIDs...

Strange... Could someone else have added an extender or repeater to your WIFI signal? Or one of your WIFI devices causing it. Things I would try... 1. Turning on the guest networks and see what...

If your router's guest network has scheduling, I suggest you use it if you want to only control the schedule WIFI times.