it is all about how you place all actors in hierarchy of blueprint, they all are relative to each other.
So if one of actors there is rotated by 90 deg, everything placed on it will be rotated.
Same goes for scaling and offsets, that all can get messy.
Whatever i have troubles with vectors i add “trace line” and set drawing to one frame or duration, this way i can see vectors in 3d in game time.
it helps understand what is wrong with my vector math.
You can also add arrow components and make them visible during gameplay, and resize up 5 or so times.
Converting world location to local location is matter of substracting local root location from world location vector.
Also for rotations you can rotate rotator, to fix wrong rotations.
Or you can clean up your actor hierarchy in blueprint.
Ps. If you want faster or more precise replies, make your questions precise and clear, it is hard to guess what is problem you have with that blueprint (or even if its in blueprint)