Keep the humidity up, yes.
But you probably should not help the duckling at this time.
Is it moving the beak? If it seems to be chewing or yawning, that means it is still absorbing the yolk. It needs to finish absorbing the yolk before it hatches the rest of the way.
https://www.backyardchickens.com/articles/guide-to-assisted-hatching-for-all-poultry.72886/
Here is a long article about assisted hatching. It has lots of good information.
That article says that ducks can take a long time to absorb the yolk and be ready to finish hatching (24-36 hours), and that pipping in the wrong place means it can take even longer yet (the article mentions 30 to 48 hours). That part is in the section titled "facing away from air cell."
I do not have much experience actually helping a chick to hatch, and none at all with ducklings. But I do have some experience with wondering, waiting, and then having the baby bird finish hatching on its own. And I have read quite a few threads from people who assisted too soon, and the baby bird ended up bleeding to death. So I would recommend waiting a while longer (but do read that article, so you can learn to recognize when is the right time to help if needed, as well as how to help.)