Since moving enchantments works from top to bottom, adding an option to always sort curses down to the very end would make it harder to remove a curse from an enchanted book. This would work great with cursery.

Thank you for your suggestion! I know I didn't respond before, but I always did want to do this. Unfortunately, starting with 1.20.5, Minecraft now has a completely fixed order in which enchantments are displayed. Funnily enough, curses are now always sorted to the top. So this is sadly no longer possible.