Book about an curator who discovers a secret while sorting out a rich man's papers and books after his death

I’m trying to find a modern novel I read around 2018 online (chapter-based on a random site). The story is in first-person from a female protagonist. I think she was called Emily or Elaine. At the beginning, she works in a bookshop and has a conversation with her boss in the early chapters. The plot involves a wealthy man who dies and leaves behind a collection of rare manuscripts/books. Emily goes to his house/estate to work on or curate this collection. The estate has a large library with very ornate bookshelves carved with mythological figures. There is a dual timeline structure, and part of the story involves uncovering secrets from the past. There is also a romance subplot with the wealthy man’s American nephew. As the story progresses, Emily discovers something in the library that connects her to her own ancestry, possibly involving a hidden treasure or secret linked to her family. The tone is modern, bookish, and slightly mysterious/cozy.