Character controller stopping.

So I'm creating a 3d platformer and for some reason when I want to jump off a wall it applies the motion but stops half a second later I don't know what is the cause of the issue it may have something to do with my other movement but I don't want to disable it because I want the player to have full control in the air. (also my code may be a mess I'm trying to fix it)

Thanks

 public class CharacterControls : MonoBehaviour
 {
     // Animator.
     public Animator anim;
   
     // Inputs.
     public InputActionReference movementControl;
     public InputActionReference UpDownControl;
 
     // character controllers
     public CharacterController controller;
     public MovingPlatForm ExternalMove;
 
     // Other Files.
     public WallJumpBoxCheck wallchecks;
 
     // Movement..
     [SerializeField] private float speed = 10;

     //Facing.
     bool directionFacing;
     public Transform character;
 
     // controls ground identifyers
     public bool isGrounded;
     public float groundDistance = 0.4f;
     public LayerMask groundMask;
     public Transform groundCheck;
 
 
     // Controls.
     public Vector3 playerVelocity;
     public Vector3 move;
 
     // Jump + Double jump.
     public float playeraction;
     public bool isjumping;
     public bool isWalljumping = false;
     [SerializeField] private float jumpSpeed = 10;
     public float gravityValue = -9.81f;
     public float wallJumpSpeed;
     public float cooldownTime;
     public float nextFireTime;
     public float wallCooldownTime;
     public float wallNextFireTime;
 
 
 
     // Camera.
     public Transform cameraMain;
 
 
     public void OnEnable()
     {
         movementControl.action.Enable();
         UpDownControl.action.Enable();
     }
     public void OnDisable()
     {
         movementControl.action.Disable();
         UpDownControl.action.Disable();
     }
 
 
     // Start is called before the first frame update
     void Start()
     {
         controller = gameObject.GetComponent<CharacterController>();
 
     }
 
     // Update is called once per frame
     void Update()
     {
         // check if player is close to the ground and return true if player is.
         isGrounded = Physics.CheckSphere(groundCheck.position, groundDistance, groundMask);
         anim.SetBool("isgrounded", isGrounded);
             
             // action to control the jump
             playeraction = UpDownControl.action.ReadValue<float>();
 
             // action to control the movement
             float movementInput = movementControl.action.ReadValue<float>();
         
             // convert movement input to vector 3
             move = new Vector3(movementInput , 0, 0);
             
             // Apply Movement.
             move.y = 0;
             controller.Move(move * Time.deltaTime * speed);
             anim.SetFloat("Speed", move.x);
         if (isGrounded)
         {
             anim.SetBool("isJumped", false);
             playerVelocity.y = -2f;
             isWalljumping = false;
             isjumping = false;
         }
        
 
 
 
         //jump
 
         // check if player is grounded and presses up
         if (isGrounded && playeraction == 1)
         {
             // start timer
             nextFireTime = Time.time + cooldownTime;
             anim.SetBool("isJumped", true);
             // move player up
             playerVelocity.y += Mathf.Sqrt(jumpSpeed * -3f * gravityValue);
 
             isjumping = true;
 
         }
 
         // Apply the movement.
         playerVelocity.y += gravityValue * Time.deltaTime ;
         controller.Move(playerVelocity * Time.deltaTime *2 );
 
         // Wall jump.
 
         // Chcek if player is not grounded and check if against the wall.
         if (!isGrounded && wallchecks.iswalled && Time.time > nextFireTime)
         {
 
             if (playeraction == 1 && !isWalljumping && Time.time > wallNextFireTime)
             {
                 // Add a next wall jump timer.
                 wallNextFireTime = Time.time + wallCooldownTime;
                 playerVelocity.y = 0;
                 // Draw ray to show that the wall has been push off of.
                 Debug.DrawRay(wallchecks.hit.point, wallchecks.hit.normal, Color.red, 1.25f);
 
                 // Apply force to character
 
                 // it fucking keeps stoping. why?
                 playerVelocity.y = wallJumpSpeed;
                 move += wallchecks.hit.normal ;
                 controller.Move(move * Time.deltaTime * wallJumpSpeed);
                 controller.Move(playerVelocity * Time.deltaTime);
                 Flip();
 
                 isWalljumping = true;
                 Debug.Log("walljump");
             }
             Debug.Log("touchwall");
             isWalljumping = false;
         }
     }
 
     public void FixedUpdate()
     {
         // get value of witch way the player is moving.
         float movementInput = movementControl.action.ReadValue<float>();
         // flipping left and right
         if (movementInput < 0 && directionFacing)
         {
             Flip();
         }
         else if (movementInput > 0 && !directionFacing)
         {
             Flip();
         }
         
     }
     void Flip()
     {
         // flip the character
         directionFacing = !directionFacing;
         character.Rotate(0, 180, 0);
     }
 
 
 }