SHMUP Boss, changing firing rate

HI,

I'm making a SHMUP game and I encounter this issue where I cannot change the rate of fire resulting in my screen flooded with projectiles, making the game unplayable. I'm using the animator to create a simple AI for the boss movement, moving from point to point on screen. Here is the script for one of the sequences:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Boss001_003_P1 : StateMachineBehaviour
 {
     public float speed = 30f;
     Transform wp;
     Rigidbody rigidbody;
     BulletPattern003a bp;
     public float rateOfFire = 2f;
     public float angleIncrement = 20f;
 
     // OnStateEnter is called when a transition starts and the state machine starts to evaluate this state
     override public void OnStateEnter(Animator animator, AnimatorStateInfo stateInfo, int layerIndex)
     {
         animator.SetBool("Next State", false);
 
         wp = GameObject.FindGameObjectWithTag("WP3").transform;
         rigidbody = animator.GetComponent<Rigidbody>();
 
         bp = animator.GetComponent<BulletPattern003a>();
     }
 
     // OnStateUpdate is called on each Update frame between OnStateEnter and OnStateExit callbacks
     override public void OnStateUpdate(Animator animator, AnimatorStateInfo stateInfo, int layerIndex)
     {
         bp.Start();
         bp.rateOfFire = rateOfFire;
         bp.angleIncrement = angleIncrement;
 
         Vector3 target = new Vector3(wp.position.x, 0f, wp.position.z);
         Vector3 newPos = Vector3.MoveTowards(rigidbody.position, target, speed * Time.deltaTime);
         rigidbody.MovePosition(newPos);
 
         if (rigidbody.transform.position == target)
         {
             animator.SetBool("Next State", true);
         }
         else
         {
             animator.SetBool("Next State", false);
         }
     }
 
     // OnStateExit is called when a transition ends and the state machine finishes evaluating this state
     override public void OnStateExit(Animator animator, AnimatorStateInfo stateInfo, int layerIndex)
     {
         bp.CancelInvoke();
     }
 }
 

Here I called out the bullet pattern on the OnStateEnter. This is the script for the bullet pattern:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class BulletPattern003a : MonoBehaviour
 {
     private float angle = 0f;
 
     public float angleIncrement = 10f;
     public float rateOfFire = 1f;
     public int numberOfSpirals = 1;
 
     public void Start()
     {
         InvokeRepeating("Fire", 0f, rateOfFire);
     }
 
     private void Fire()
     {
         float spreadAngle = 360f - (360f / numberOfSpirals);
 
         for (int i = 0; i <= (numberOfSpirals - 1); i++)
         {
             float proDirX = transform.position.x + Mathf.Cos(((angle + spreadAngle * i) * Mathf.PI) / 180f);
             float proDirZ = transform.position.z + Mathf.Sin(((angle + spreadAngle * i) * Mathf.PI) / 180f);
 
             Vector3 proMoveVector = new Vector3(proDirX, 0f, proDirZ);
             Vector3 proDir = (proMoveVector - transform.position).normalized;
 
             GameObject pro = ProjectilePool.projectilePoolInstances.GetProjectile();
                 pro.transform.position = transform.position;
                 pro.transform.rotation = transform.rotation;
                 pro.SetActive(true);
                 pro.GetComponent<EnemyProjectileProperties>().SetProjectileDirection(proDir);
         }
                 
         angle += angleIncrement;
 
         if (angle >= 360)
         {
             angle = 0f;
         }
     }
 }
 

When testing the bullet pattern on its own, I can manipulate all of its variables. However, when implemented onto the animator, I cannot control the rate of fire. Changing the angle of increment works fine but nothing seems to work for the rate of fire. Is implementing Start(); in the animator the wrong move? Or am I missing any steps in between? Please advise. Thank you.