My Car keeps not moving when its already at 0 Velocity HELP

Hi My Game is an Arcade Racing game. thats why i want to use addforce for forward and backward movement. My Problem is that the Car/Rigidbody is getting stuck if the Car has 0 velocity. it start turning upside down and may get unstuck after a couple of forward/backward keystrokes. Making the player spawn in mid air and dropping down fixes the issue if playerinput is there before hitting the ground. I am Using addforce only for forward and backwards. Turning is determind by the steeringangle with wheel colliders (2 wheels in front). rear wheels for force.

I am pretty new to C# and Unity in general. And i couldnt find anything that would make the player not get stuck there. maybe you guys can help me`using System.Collections; using System.Collections.Generic; using UnityEngine;

public class SimpleCarController : MonoBehaviour { private Rigidbody rb;

 void Start()
 {
     rb = GetComponent<Rigidbody>();
 }
 public void GetInput()
 {
     m_horizontalInput = Input.GetAxis("Horizontal");
     m_verticalInput = Input.GetAxis("Vertical");
 }

 
 public void Accelerate()

 {

 
     if (Input.GetKey(KeyCode.W) || ButtonF.Forward == 1)
     {
         Vector3 forceToAdd = transform.forward;
         forceToAdd.y = 0;
         rb.AddForce(forceToAdd * speed * 10);
     }
     else if (Input.GetKey(KeyCode.S) || ButtonB.Back == 1)
     {
         Vector3 forceToAdd = -transform.forward;
         forceToAdd.y = 0;
         rb.AddForce(forceToAdd * speed * 10);
     }

     Vector3 locVel = transform.InverseTransformDirection(rb.velocity);
     locVel = new Vector3(0, locVel.y, locVel.z);
     rb.velocity = new Vector3(transform.TransformDirection(locVel).x, rb.velocity.y, transform.TransformDirection(locVel).z);




     // Abruf des Gameobjektes 
     var gmj = GameObject.Find("CountdownText");
     //Nullcheck um Nullrefex zu vermeiden
     if (gmj != null)
     {
         //Abruf des Script objetes aus dem Gameobject
         var comp = gmj.GetComponent<CountdownTimer>();
         if (comp != null)
         {
             //Script Aktivitätscheck
             if (!comp?.countdownActive ?? false)
             {
                 rb.velocity = new Vector3(0, 0, transform.TransformDirection(locVel).z);
             }
         }
     }



 }



 private void UpdateWheelPoses()
 {
     UpdateWheelPose(rearDriverW, rearDriverT);
     UpdateWheelPose(rearPassengerW, rearPassengerT);
 }

 private void UpdateWheelPose(WheelCollider _collider, Transform _transform)
 {
     Vector3 _pos = _transform.position;
     Quaternion _quat = _transform.rotation;

     _collider.GetWorldPose(out _pos, out _quat);

     _transform.position = _pos;
     _transform.rotation = _quat;
 }


 private void FixedUpdate()
 {
     Accelerate();
     UpdateWheelPoses();
     GetInput();



 }


 private float m_horizontalInput;
 private float m_verticalInput;
 private float m_steeringAngle;
 public float speed;

 
 public WheelCollider rearDriverW, rearPassengerW;
 
 public Transform rearDriverT, rearPassengerT;
 
 public float motorForce = 50;
 public float gravityMultiplier;
 

}`