Refrigerator Fan
To help circulate the cool air in your refrigerator try a small fan made specifically to do just this. They sell them on Ebay and at most RV stores. Campers use these too for the same propose.
They are battery operated, and very low voltage so they run for about 3-4 weeks before you have to change batteries. (big “D” batteries) You might even get two of them depending on your refrigerator layout. I have a two level fridge so i have one down low and one up high. This does seem to make the fridge colder with the air circulated from the freezer spillover. I think it makes a real difference.
I use a very small 3″ computer fan wired to the compressor so that it runs when the compressor runs. It’s kept the fridge temperature constant (including the furthest areas) and reduced ice buildup.