You missed the perhaps most important datapoint: how often and many times did you open the freezer? Side loaded freezer and fridges are extremely inefficient because all the cold air is let out when you open the door.
We lost power for 4 days, but I packed in every water bottle I could find before hand, and everything remained frozen for the entire period. Literally almost no space left for air.
We also did not open it, of course.
By the time we were able to find a gas station with dry ice we were out looking for open wal marts at a 73 mile radius from the house (Columbus Texas). The dry ice was not significant enough to do much more than get the fish cool. It was too late.
Why not tip the freezer / fridge onto its back? So that doors open "up"?
Aware they're typically not perfectly flat on the rear face, but close enough you could support it with minimal work. And if it's unpowered, there's no need for clearance back there.
Unless they have drawers https://pc.vertaa.fi/250x250/102776708.jpg