So I’m having the same problem. It started about a week ago and my connection drops daily and I have to reboot my router. I was told in another forum to try and turn smart WiFi off, which I did yesterday, and yet I have woken up this morning with no connection.
The strange thing is that SOME devices remain connected. For example my Apple TV and Virgin set top box are still connected and I can watch apps like Netflix, but my main devices like phone and tablets have reverted to 4G. I’ve had to reboot the router daily to get a connection, and then it drops again the following day.
I’ll be honest, I’m a bit of a novice when it comes to this. All the numbers and tables and stuff that have been posted by the OP go over my head and I’ve no idea what any of that means haha. All I know is all of a sudden my Virgin broadband doesn’t seem to want to do what it’s meant to.