Thanks to the known (for at least a year and a half?) issue of “New Post” at the top right failing to use autosave, I lost two hours of work. As is, I feel distraught enough that I can’t quite restart in good faith at the moment.
Let this be a lesson: don’t write in WordPress’s editor. That’s a shockingly negligent problem, considering the volume of threads wondering where an auto-saved post went and being told, “Oh, did you start from there? Yeah, it’s gone forever. Oops!”