Ok, and how can i prevent the wiggling back and forth via this diagonal line? Is that what simple smooth is for?
You can use either simple smooth, the funnel modifier or the raycast modifier for that. They each have their own pros and cons. In this case I think the raycast modifier is appropriate (with graph raycasting enabled, not physics raycasting).
The path still sends the agent into a hole in the ground, not taking into account the unwalkable nodes around the hole:
I can’t see how that path started. Check again that you have graph raycasting enabled on the raycast modifier, and that your simple smooth modifier is not too aggressive.