@Kevin_Z 

Hi Kevin.

Yes I have tried this and I still get the WAN, LAN turning itself on and off periodically. The light never goes red, it remains green the entire time. Its is connected to a Linksys AX5400 WiFi 6 Router. 

I have tried various combinations of static / dynamic IPs, DHCP auto/on/off, changing IP subnets, cloning MAC addresses. I feel the issue maybe something that is happening with the DNS (I have tried using the gateway IP and also 8.8.8.8 directly). I've tried using the WAN and the LAN ports. Factory resets. Changing cables.

The internet works, but it just occasionally drops out and has trouble connecting. For example a webpage might say "This page cannot be found". It is most noticable during zoom calls and the connection is lost.

As another aside, I have trouble connecting iphones to the 5G network. It connects and disconnects in a cycle every 10 seconds. Whereas it works fine on MacBooks. 

  @Kevin_Z I will try changing it to router mode later then

The iPhone having trouble connecting is a iPhone SE (2020), using iOS 15.6. There is no VPN or other settings on the phone. Tried changing channels, bandwidths etc. The strange thing is this only became a problem once the connectivity issue arose. Previously it could connect to the 5G perfectly fine. I first noticed it when I couldn't connect to either and had to turn Smart Connect off. Then it could connect to both fine. Now the 5G cannot be connected to. Laptops, apple TV, all other devices connect to the 5G wifi fine.