In my 1.20.4 world I have never struggled with mob drops, but playing that same world on 1.20.5, I can no longer get anything from a mob, whether it hostile or not, I can't get leather, raw beef, wool, raw mutton, feathers, raw chicken, shulker shells, ender pearls, blaze rods, you name it. I can't get unbreaking books from villagers because I have no books/leather so I can't get those on my elytra.