Also remember that a thermometer that measures the AIR TEMP on the fridge is not accurate! Per my friend who is in the refrigeration biz the ONLY accurate way to assess temp is to place a thermometer probe in a cup of liquid. I had forgotten this tidbit from my past learning LOL.
These small TC refrigerators can inc. dramatically in air temp and then take hours to cool back down. But the INTERNAL temps of the food in there may very well be within normal/safe limits.
We had a small hanging mercury thermometer and also a digital probe with a wire. Both of those showed that refrigerator was "above safe limits" for multiple hours a day.
But once I put the digital probe in a small cup of liquid (I used a large pill bottle and drilled a small hole in the top and add a dab of silicone to seal... make sure your probe is waterproof). The hanging thermometer showed that the air temp was "too warm" during multiple periods during the day , but the digital one stayed within the safe range for food. The pill bottle also made it easy to unscrew the cap and add water or clean bottle.
But we did have to try numerous fixes including adding a baffle that kinda worked, but we then removed and replaced with the fan.
If you are having trouble finding a waterproof probe, try using a kitchen thermometer. Just make sure they are calibrated low enough. They come in both wired and wireless versions that are usually cheaper than an "outside" waterproof thermometer.