@Frank. Dirty coils will cause major problems. Most people clean the coils when the unit stops cooling. By then it’s probably too late. The coils should be cleaned at least once a year and more if you have pets.
Do you hear a click every few minutes coming from the compressor area? Duo you see any signs of oil around the compressor or the coils? If everything is running that you might have a bad pcb or a problem on the sealed system. This would be difficult to diagnose without being in front of the refrigerator.