There should be a sticker or plate on the thing somewhere with the model code, manufacture date, etc.

I am wondering if the defrost heater is working frequently or continuously, thereby creating a heat load for the compressor to struggle with. Or the control/timer thingamajig (TM) is done gone wrong.

Compressors tend to last almost forever. The control units and air circulation fans, not so much.

Sometimes the exposed coils on the back or bottom of the fridge just need to have the dust bunnies cleaned off, there may even be a (broken) fan if the coils are tucked underneath.

Lots of things can cause a fridge to run much more than it should, often these things can be ignored for years, you just keep paying for the electrocity.