We've seen the canonical Kakashi, the mask-wearing, mission-focused, tragedy-haunted sensei, but the version in 'Icha Icha'-themed fanfic always fascinated me more because it feels like a logical extension of his established character, not a total break from it. The man reads those books openly, almost defiantly. That's the key. He uses them as a shield, a performance of laziness and perversion to keep people at a distance. So a fic that explores his romantic side through that lens isn't about him suddenly becoming a smooth talker. It's about the dissonance. He knows every trope in the book, could probably write a better romance novel than Jiraiya, but applying any of that to his own life would be hilariously, tragically awkward.
I think the best stories use the 'Icha Icha' knowledge as a form of emotional illiteracy. He can deconstruct the three-act structure of a confession scene but wouldn't recognize a real, tender moment if it hit him with a Rasengan. The romance comes from someone—maybe an OC, maybe a canon character—seeing past the book and the mask to the guy who uses both as armor. They don't want the fictional lover; they want the man who finds comfort in those fictions because his own reality has been so painful. The 'Icha Icha' becomes a shared language, a way to be vulnerable through a joke. He might quote a terribly flowery line to lighten a mood, and it works precisely because everyone knows it's a quote. It's his version of holding hands.