Did you seal outside vents after Residential refer install?

Some residentials place the condenser on the fridge's side walls, instead of having a finned visible heatsink one can easily vent.

Besides extra insulation, proper venting of condenser it the best way to increase efficiency, and also the easiest way to ensure poor performance if not vented properly.

Mine DC compressor fridge sucks coolest possible filtered ambient air and pushes it only once through condenser, across compressor and controller then out of the fridge cabinet entirely.