Mmhh, we don't have a temperature gauge on our Engel MT 27F at all. It is continuously adjustable on a scale from 1 to 5 with a wheel. It has a temperature range of +5°C to -18°C, which is about 41°F to 65°F. I usually don't set it higher than 1 on the scale, because otherwise the inside starts to freeze.
The fridge, like many others, has a practical inner basket. Such baskets are also available individually. Thus, the fridge can be easily packed (e.g. from the house into the rig and vice versa) and the contents can be removed completely easily - such as for cleaning - the box. For packing inside, we like to use such small leak-proof plastic boxes for individual things. Then everything is not lying loose in the fridge and can be removed more easily. With this you can also sort things thematically and everything doesn't tumble around - especially when it gets rough on dirtroads.
We always make sure that the fridge is well filled, because, also the contents of the fridge acts similar to a cold accumulator. Beer cans are well suited for this - hahaha. So the fridge does not have to cool down the air inside.