editing and creating bookmarks, as well as organising them into folders, as well as opening multiple bookmarks/folders simultaneously and bookmarking multiple tabs at the same time all work fine for me on Firefox on Android
Weird. I have a single "Bookmarks" menu item. Opening that shows them. I can tap to open, or "X" to delete. Long-press to select (multiple) which reveals a share icon and a triple-dot with open, open in private or delete. That's it. There is no edit or move operation.
(I noticed adding to a folder appends, and for a while was carefully shuffling between folders to sort, then realized they'd given up on bookmarks so I should too.)