ECS - Convert rotation to normalised vector.

This seems strange, I have a pretty straightforward thing, I have an entity, I need to move it along it's own rotation for a normalised vector.

Can't figure it out. I have a rotation, a quaternion and I would assume I'd be able to get a vector from it. But no luck. I can't convert that quaternion to a vector.

Code (CSharp):

1.  Vector3.Normalize(target.Value);
2. "Cannot implicitly convert type 'UnityEngine.Vector3' to 'Unity.Mathematics.quaternion"

I've tried a bunch of different things as well, but in the end it's probably my lack of properly understanding quaternions. So, how do I convert a quaternion to a vector that I then can add to my physics body like this;

Code (CSharp):

1. physicsVelocity.Linear = vector;

 

This code works, but please tell me a better way, this hacky bit can't be good

Code (CSharp):

1.                 Quaternion currentRotation = rotation.Value;
2.                 var angle = 360 - currentRotation.eulerAngles.z;
3.                 var rad = angle * Mathf.Deg2Rad;
4.  
5.                 // covert the angle to a 2d vector
6.                 Vector2 v2 = new Vector2(Mathf.Cos(rad), Mathf.Sin(rad));
7.                 float3 velocity;
8.  
9.                 velocity = new float3(v2.y, v2.x, 0f);
10.                 physicsVelocity.Linear = velocity;