I'm trying to make my player move a certain speed I want it to go, but I'm having a hard time. (3D project)

I'm trying to make my player move faster in my project and I thought this code should work but it didn't. I tried copying with the same code my jump button uses but just change "up" to "forward" and "VelocityChange" to "acceleration".

 // Start is called before the first frame update
 void Start()
 {
     rigidbodyComponent = GetComponent<Rigidbody>();
 }

 // Update is called once per frame
 void Update()
 {
     // Check if Space key jumps the player
     if (Input.GetKeyDown(KeyCode.Space)) 
     {
         SpaceKeyWasPressed = true;
     }

     horizontalInput = Input.GetAxis("Horizontal");

     verticalInput = Input.GetAxis("Vertical");

     if (Input.GetKeyDown(KeyCode.W))
     {
         wKeyWasPressed = true;
     }
 }
 //FixedUpdate is called once every update
 private void FixedUpdate()
 {
     if (Physics.OverlapSphere(groundCheckTransform.position, 0.1f).Length == 1)
     {
         return;
     }
  // The Jump Code to make my player jump
     if (SpaceKeyWasPressed) 
     {
         rigidbodyComponent.AddForce(Vector3.up * 5, ForceMode.VelocityChange);
         SpaceKeyWasPressed = false;
     }

     rigidbodyComponent.velocity = new Vector3(horizontalInput, rigidbodyComponent.velocity.y, verticalInput);
     //make player move a certain speed
     if (wKeyWasPressed)
     {
         rigidbodyComponent.AddForce(new Vector3.forward * 5, ForceMode.Acceleration);
     }
 }

}