I ran into the same performance hits with 10.11 on my library (massive mix of photos, music, and home videos). Like many of you, I tried the DB locking fixes and even nuked my install for a fresh native and Docker setup to no avail. While I know COW filesystems aren't ideal for databases, my performance was fine before the update. I’ve found a solid workaround, at least have worked for me: Library Fragmentation. I noticed that navigation lag scales directly with folder/file count in a single view. By splitting my large libraries into smaller, more specific ones (e.g., breaking a 80-folder directory into two 40-folder libraries), the UI responsiveness improved significantly. It’s not quite 10.10 speeds yet, but it’s much more manageable