We don't have enough information to know exactly who Karen is. She could be an ordinary person, a student, a teacher, or just someone who likes to read stories.
Given only 'dateline karen read story', Karen's identity remains a mystery. She might be a staff member at Dateline who was reading a story for work purposes. Or she could be a person who was interviewed by Dateline and was reading a story during the interview, or she could be an ordinary person whose story - reading experience is being highlighted in relation to Dateline.
It's hard to say for sure. 'Karen' could be a blend of real incidents and creative imagination. Sometimes, such stories take real-life inspirations but are embellished for entertainment value.
I don't think there was a character named Karen in Punisher comics. Usually, the main characters and well-known ones are pretty distinct, and I haven't come across a Karen in this series.
Without more context, it's hard to say exactly who they are. They could be a family, with Karen Ann being an individual within the Quinlan family. Maybe they are people who have had some interesting or important experiences that are worth sharing in this story.
In 'Karen Eiffel Stranger than Fiction', Karen Eiffel is a key character. She is a writer, and her actions and the story she is writing are central to the plot. Her role creates a unique situation where the fictional world she is creating intersects with the real life of the other main character in a very strange and unexpected way.