WiFi dropping all the sudden?

We have the free family filter set on both an iPad and a computer that our son uses. Have been using it for years with no problems, very happy with it. Very recently, we are experiencing intermittent connection issues just on those two devices. Other devices in the house that don’t use the filter are not having any issues. Also, son’s devices that are having the issue use the same router as our Apple TV, but the Apple TV is not having issues. The only thing the 2 devices with issues have in common is the use of the CB filter.

He can usually get it to work again by turning off wifi on both devices and then turning it back on, but it only works for 20-30 minutes or so before the connection drops again.

Any ideas what we should do?