Hey I also found this quote from Aron on the forum, in another thread (AI Path not working with Rigidbody2D? - #2 by aron_granberg)
Hi
AIPath works with a rigidbody, but only by modifying its velocity directly. It does not move using forces. So it will collide with things, but it will not react to other kinds of forces.
To get a movement script that is force-based, you’d have to write your own. See Writing a movement script - A* Pathfinding Project
Maybe this could help with jittering, while staying performant? Let me know what you think of this idea. (EDIT: I see this is in reference to AIPath, not Astar as a whole, but it’s probably worth a try)