Can you manually select the required network 3G vs 4G rather than let the modem automatically select?
Re: Netwrok s
You have posted your message in the section of this community given over to Nighthawk WiFi Routers. (This is easily done, given Netgear's complicated community structure.)
Many questions apply to different types of device, there may be useful responses here, but Mobile Routers don't have much in common with plain routers so you might get more help, and find earlier questions and answers specific to your device, in the appropriate section for your hardware. That's probably here:
Mobile Routers, Hotspots & Modems
I will ask the Netgear moderator to move your message.
In the meantime you could visit the support pages:
Support | NETGEAR
Feed in your model number and check the documentation for your hardware. Look at the label on the device for the model number.
You may have done this already. I can't tell from your message.
I mention it because Netgear stopped supplying printed manuals and CD versions some years ago and people sometimes miss the downloads.