Slow falling

Hello,

I am a beginner with coding and followed a tutorial on YouTube for 3rd person movement with Unity's input manager by Sebastian Graves, in the tutorial we created scrips to move and animate a character but in the tutorial whenever the character is in the air movement is blocked. I found out that it was because of a boolean called "isInterancing", I manged to remove the if statement that blocks movement when the character is falling but when after doing that the character now falls too slow as shown below, I can't figure out why, so I hope someone can help me please.

 public class PlayerLocomotion : MonoBehaviour
 {
     PlayerManager playerManager;
     animatorManager animatorManager;
     inputManager inputManager;
 
     Vector3 moveDirection;
     Transform cameraObject;
     Rigidbody playerRigidbody;
 
     [Header("Falling")]
     public float inAirTimer;
     public float leapingVelocity;
     public float fallingVelocity;
     public float rayCastHeightOffSet = 0.5f;
     public LayerMask groundLayer;
 
     
     [Header("Movement Flags")]
     public bool isSprinting;
     public bool isJumping;
     public bool isGrounded;
 
 
     [Header ("Movement Speeds")]
     public float walkingSpeed = 1.5f;
     public float runningSpeed = 5;
     public float sprintingSpeed = 7;
     public float rotationSpeed = 15;
 
 
     [Header("Jump Speeds")]
     public float jumpHeight = 3;
     public float gravityIntensity = -15;
 
 
 
     private void Awake()
     {
 
         playerManager = GetComponent<PlayerManager>();
         animatorManager = GetComponent<animatorManager>();
         inputManager = GetComponent<inputManager>();
         playerRigidbody = GetComponent<Rigidbody>();
         cameraObject = Camera.main.transform;
     }
 
     public void HandleAllMovement()
     {
 
         HandleFallingAndLanding();
 
        if (playerManager.isInteracting)
           return;
 
         if (isJumping)
            return;
 
         HandleMovement();
         HandleRotation();
     }
     private void HandleMovement()
     {
         if (isJumping)
             return;
         moveDirection = cameraObject.forward * inputManager.verticalInput;
         moveDirection = moveDirection + cameraObject.right * inputManager.horizontalInput;
         moveDirection.Normalize();
         moveDirection.y = 0;
 
         if(isSprinting)
         {
             moveDirection = moveDirection * sprintingSpeed;
         }
         else
         {
             if (inputManager.moveAmount >= 0.5f)
             {
                 moveDirection = moveDirection * runningSpeed;
             }
             else
             {
                 moveDirection = moveDirection * walkingSpeed;
             }
         }
 
 
        
        
         
 
         Vector3 movementVelocity = moveDirection;
         playerRigidbody.velocity = movementVelocity;
 
 
     }
 
     private void HandleRotation()
     {
         if (isJumping)
             return;
 
         Vector3 targetDirection = Vector3.zero;
         targetDirection = cameraObject.forward * inputManager.verticalInput;
         targetDirection = targetDirection +cameraObject.right * inputManager.horizontalInput;
         targetDirection.Normalize();
         targetDirection.y = 0;
 
         if (targetDirection == Vector3.zero)
             targetDirection = transform.forward;
 
         Quaternion targetRotation = Quaternion.LookRotation(targetDirection);
         Quaternion playerRotation = Quaternion.Slerp(transform.rotation, targetRotation, rotationSpeed * Time.deltaTime);
 
         transform.rotation = playerRotation;
     }
 
     private void HandleFallingAndLanding()
     {
         RaycastHit hit;
         Vector3 rayCastOrigin = transform.position;
         rayCastOrigin.y = rayCastOrigin.y + rayCastHeightOffSet;
 
         if (!isGrounded&& !isJumping)
         {
             if(!playerManager.isInteracting)
             {
                animatorManager.PlayTargetAnimation("Falling", true);
             }
 
             inAirTimer = inAirTimer + Time.deltaTime;
             playerRigidbody.AddForce(transform.forward * leapingVelocity);
             playerRigidbody.AddForce(-Vector3.up * fallingVelocity * inAirTimer);
             }
 
         if(Physics.SphereCast(rayCastOrigin, 0.2f, -Vector3.up, out hit, groundLayer))
         {
             if (!isGrounded)
             {
                 animatorManager.PlayTargetAnimation("Landing", true);
             }
 
             inAirTimer = 0;
             isGrounded = true;
 
         }
         else
         {
             isGrounded = false;
         }
     }
 
     public void HandleJumping()
     {
 
         if(isGrounded)
         {
             animatorManager.animator.SetBool("isJumping", true);
             animatorManager.PlayTargetAnimation("Jumping", false);
 
             float jumpingVelocity = Mathf.Sqrt(-2 * gravityIntensity * jumpHeight);
             Vector3 playerVelocity = moveDirection;
             playerVelocity.y = jumpingVelocity;
             playerRigidbody.velocity = playerVelocity;
         }
     }
 
 
 }