I can't download a world from the file manager tab. I've tried selecting all the available folders, downloading them, extracting them, and placing them into a single folder in my local saves folder, but the world still doesn't show up.
I've done this before successfully multiple times, and every time I've done so the file manager tab shows folders named "advancements" and "data" (among others such as "cache"). This time, those two folders are absent. Could this be part of the problem?