The problem is almost definitely in the drainage, not in the drum motor. If it's spinning but the clothes are still soaked, it means the water isn't draining properly during that phase. Besides the pump filter (which was already mentioned), also check the entire drain hose: sometimes a small kink or bend forms that blocks the flow without you noticing, especially if the washer is built-in or pushed right up against the wall.
There's a trick that works: open the front panel (if it has one) or access it however you can, locate the internal drain tube that runs from the drum to the pump, and make sure it's properly connected at both ends. Sometimes it comes loose a bit over time. If you see lime deposits or dirt buildup around it, that can also be slowing down the drainage. Since the washer is new, it's probably not a lime issue, but it's worth checking.
If it's still the same after you've checked all that, then it really is a factory defect and you should contact LG directly, because a new washer should spin correctly. But 9 times out of 10 when this happens it's because of the drainage.