I’ve written to a few authors - well known in their genre but not mega stars like Stephen king or jk Rowling. They all wrote back to me and somewhere in our email exchange they said they don’t get many emails ( which surprised me. They get plenty of reviews and press coverage.) in my email I just expressed specific things they wrote and how it impacted my life and thanked them for writing the book. Brief exchanges, we didn’t become pen pals or friends or anything but they were all very kind.