Sure is. The Punisher has been a staple in the Marvel Comics universe for quite some time. His anti-hero persona and violent methods make him a distinctive character.
Some of the top Punisher stories on Marvel Unlimited include 'Punisher: War Zone' and 'Punisher MAX'. These offer intense action and deep character exploration.
If Peter Parker became The Punisher, it would be a huge shift. Peter is typically known for his sense of mercy and trying to rehabilitate villains. As The Punisher, he'd be more brutal. This could lead to a darker and more divided Marvel Universe. His relationships with other heroes would be strained. For example, Daredevil, who often tries to uphold the law within the legal system, would likely oppose Peter's new methods.
In the comics, the Punisher isn't simply heartless. His actions are a result of his traumatic past and a determination to fight crime by any means necessary. It's a mix of passion and a warped sense of morality.
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.