You won’t have any luck trying to do MASS related logic in blueprints, c++ is required for anything more than just ambient crowds. As far as i know you still have to write your own processors for pathfinding, attacking etc. Essentially MASS is just a data oriented framework for managing crowds of entities.
X15 has a good resource for learning MASS in Unreal :
Mass Entity UE5 Mass | X157 Dev Notes
Apparently 5.6 is adding more functionalities to MASS AI but i have yet to try anything with it.
If anyone finds this erroneous feel free to correct me, i do not have that much experience with MASS since digging into the Matrix Demo a while back.