I was skeptical, but a fan does seem to help

The router behavior with or without the screen makes no sense. Pretty crazy. I just have to wonder at times about how the Nokia router does handle the cellular signals. I had mine in the upstairs kitchen window with line of sight to the tower and it would at best get a weak signal. I moved it to the left side of the window vs the right side without line of sight and it receives a stronger signal. It is as if a reflected signal off the cabinets to the right hand side is better. At times I agree there doesn't appear to be any reasoning behind the location in other than trial and error. I have been thinking of buying an external MIMO yagi antenna since I have line of sight to the tower 5.3 miles away. None of the places where it tends to work are very desirable. I wish they had an interior antenna array on a 20-30 foot cable so the placement of the router could be optimized for wireless delivery on the local LAN. The attempt to fold both the cellular and WIFI into a tiny single package compromises both solutions or at best one or the other. With the 802.11ax radios they do appear to get pretty good coverage here in our 3300 sq ft two story home. I was skeptical of it at first but gave it time to prove itself and so far it has. It is much better than the unit the service provider in CA provisioned us with. That one really was a hard reboot often like every few days or weekly at best just to have a pitiful 15-18 Mbs down on DSL and for more cost than here. The T-Mobile solution is commonly 10x the up/down speeds so I don't have anything to complain about. This was our only real option and it works pretty well. Most of the time.