Just went searching for something like this as my wife wanted to start a “journal”. The requirements were simple, private, nothing too crazy complicated to use, web interface, easy setup and tear down (in case she didn’t like it). Started up an instance of Ghost, way overkill, was looking at WriteFreely, stood up an instance of Bookstack. She’s trying it out now, nothing bad to report so far. The hierarchy is a bit confusing to grasp but when you put it in the context of something like shelve = My Journal, Book= 2023 Vacation or 2023 or Homeschooling, Chapters = 1st week of Vacation or First year Homeschool, Pages = Todays date. It started clicking with her a bit more. If you find something better, please report back!