Whirlpool fridge isn’t cold. Notice this at the bottom of the freezer. Am I correct in assuming it is freezing over? And if so, how do I fix it?

Its most likely a defrost issue,... unless theres a clear defect with door seals or someone left door ajar overnight. 3 parts involved Heater. - Diagnosed with multimeter. It either has continuity or not (or ohms value) Bimetal on some models. They can be tricky to diagnose as they may show continuity sometimes but can be erratic in reliability. Inexpensive enough to just replace blindly. Newer models have replaced bimetal with a thermistor and also Inexpensive to replace. Older models have a mechanical timer. They can be manually advanced into defrost cycle with a flat screwdriver. If defrost heater starts sizzling, then its a faulty timer. Newer fridges have the "timer" integrated in to main board. Youll have to locate the tech sheet that tells you how to enter in to a "forced defrost cycle"

When this happened to me (frozen solid freezer, but only 50 degrees in the fridge) I had a ext. warrantee from a 3rd party. They replaced the entire circuit board, and then left. It did not fix anything. NOTHING Then they came back and replaced another part and left. It fixed nothing. NOTHING Then they came back replaced this part (Defrost sensor) The guy said it's the only possible thing left. It's a $20 part. I always thought they replaced the most expensive thing first because I had that extended warranty—a crooked place. Seems like this should be the first thing to look at just based on the name on the part

Yes, that looks like frost buildup behind the evaporator cover, which can block airflow and leave the refrigerator section warm. Fully defrost it by unplugging the unit for 24–48 hours with both doors open. If the frost returns, the defrost heater, thermostat/sensor, fan, or control board will need to be tested.