Artemis in the 'Can't pick up girl in a dungeon' OVA is a character within the series. She likely has her own backstory and role within the story's world.
Not at all. Whether it's right or wrong to pick it up depends on various factors like your expectations, the reviews you've heard, and your previous experiences with similar manga. But give it a try and see if it suits you.
I think the Can't Pick Up Girl in a Dungeon OVA story could be a standalone tale or a continuation of certain storylines from the main series. It could also introduce new elements to keep fans engaged.