Rotate and move character with Joystick

assuming your joystick inputs are relative to the main camera... 1) keep a reference to the Camera's transform in a variable.... camTran

2) now you can generate a vector based on the camera's camTran .forward and camTran.right multiplied by the joystick inputs e.g. Vector3 joyFacingVector = ((camTran.forward joy.Y) + (camTran.right joy.X)).normalized; note:- if your joystick is centered.... with magnitude 0, then your joyFacingVector needs to be just camTran.forward

3) now you can rotate the tank towards that vector.
Vector3.rotateTowards(tank.transform.forward, joyFacingVector, maxAngleDelta, maxMagDelta); https://docs.unity3d.com/ScriptReference/Vector3.RotateTowards.html

Note:- for the turret.. you can face that forwards after rotating the base... so it still shoots forwards e.g. 4) Turret.transform.forward = camTran.forward; but that all depends what you want from your controls :)

its a bit late

but i did it like this

float angle = Mathf.Atan2(joy.Horizontal, joy.Vertical) * Mathf.Rad2Deg; this.transform.rotation =Quaternion.Euler(new Vector3(0, angle, 0));