Hi, thanks for the help! In the end, none were quite right to get the direction between two game objects in a vector 3 (with possible normalization), aka heading.
I ended up writing my own action. Attached.
This action calculates the direction between two gameobjects (source and target) and gives a vector 3 direction. If you choose normalization, it also calculates the distance (magnitude) and normalizes the direction to give a "heading". This could be used to steer/point one gameobject towards another. The normalization has a separate toggle because it take an extra calculation to do it. Therefore if you don't need it, untoggle it.
You may not need the distance/ un-normalized direction if you are using the normalize direction (heading), but I gave the variable outputs anyways, since they are already being calculated (you might as well get access to them, in case you want to use them elsewhere).