How much room do you have around the refer? Have you looked into ventilation around it or adding a DC fan to move air around the back?
Polyiso rigid sheets for best R-value, corners and gaps filled with a closed-cell spray.
Not only ensuring that ventilating the hot bits don't get blocked, but adding to that will help a lot as well.
Measure AH per 24 hours before and after, similar loads, temps and opening patterns, and report back here!