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.
I'm not sure specifically as I haven't read this particular 'zettai ni yatte wa ikenai isekai novel'. It could be about various things common in isekai novels like a protagonist being transported to another world but with some kind of moral or rule that they must not do certain actions (as the 'zettai ni yatte wa ikenai' part might imply).
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.
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.
Well, without having read the actual 'zettai ni yatte wa ikenai isekai shoukan novel', it's difficult to give a detailed account. However, given the title, it could be about a character who is summoned to an isekai world and discovers there are certain actions that are strictly prohibited. Maybe it involves a protagonist who has to navigate this new world while avoiding these forbidden deeds to achieve a certain goal, like saving the isekai or getting back home.