@siikalahna
He may actually not be that strong. He just has more skills to use so he appears stronger than what he actually is. Because he has a lot of specific skills, but just with limited usability, he appears to be amazingly talented. And he is only made to look even stronger because he has enough of a variety where most situations are somewhat covered. At least enough so that he wont die easily and can kill possible or escape if needed.
He basically is playing with an inflated stat line. Kind of like how some games only count certain skills/actions towards leveling up. He may be max level in one thing, but since it isnt a skill which counts towards overall level, he gains 0 xp thus his low level.
MC also does not fight a lot. He harvests and forages for food, and crafts for the majority of his time. He kills here and there, but has yet to go power leveling and can't leech xp from others.