I'm skeptical of most fiction in this space because it oversimplifies the job. Real coaching is 90% man-management, media training, and dealing with agents. The on-pitch tactics are a small part. I've yet to read a novel that captures the soul-crushing boredom of film review or the awkwardness of disciplining a millionaire player.
Maybe that's just not dramatic enough. The closest I've found are biographies. Carlo Ancelotti's 'Quiet Leadership' is basically a novel's worth of anecdotes about handling egos at Madrid, Chelsea, and Milan. He talks about decision-making in a way that feels like storytelling. For authentic perspective, sometimes reality is stranger and more insightful than fiction.