Oh yes, low cellular signal connection and no Wifi will definitely draw down the battery.I have similar SOT with my iPhone. My problem is it's in a no wifi, 1-2 bars area 9-10 hours a day. Plus tasks like CGM, Home, Find My and Siri drain a ton of the battery in the background. I plan on trying out the Air for a week. If that doesn't work out, I'll just grab the regular 17.
You might be a candidate for the Pro Max with the larger battery ?