How do I fix collisions while using this PlayerController script?

Hi, I'm new to Unity and programming, I've managed to write a PlayerController script (watching some tutorials) but I think it's wrong. I have collisions only with a rigidbody but when i add it to the player it goes up, if I freeze the Y coordinate then it works but collisions works in a strange way, sometimes while hitting other objects boxes the player get "launched" in a direction and can't move anymore. Can anyone help me fix this script?

 using UnityEngine;
 using UnityEngine.UI;
 using UnityEngine.SceneManagement;
 
 public class PlayerController : MonoBehaviour
 {
     public float moveSpeed;
 
     public CharacterController controller;
 
     public GameObject bulletPrefab;
     public Transform bulletSpawn;
 
     public int stardustcount;
 
     public Slider stardustbar;
 
     void Start()
     {
         controller = GetComponent<CharacterController>();
     }
 
     void Update()
     {
         transform.position += transform.forward * Time.deltaTime * moveSpeed;
 
         if (Input.GetButtonDown("Fire1"))
         {
             Fire();
         }
 
         if (Input.GetButton("Fire3"))
         {
             moveSpeed = 10;
         }
 
         else
         {
             moveSpeed = 30;
         }
     }
 
     void Fire()
     {
         var bullet = (GameObject)Instantiate(bulletPrefab, bulletSpawn.position, bulletSpawn.rotation);
         bullet.GetComponent<Rigidbody>().velocity = bullet.transform.forward * 60;
         Destroy(bullet, 5.0f);
     }
     
     void OnTriggerEnter(Collider other)
     {
         if (other.gameObject.CompareTag("Stardust"))
         {
             Destroy(other.gameObject);
             stardustcount = stardustcount + 1;
             stardustbar.value = stardustcount;
         }
     }
 }

The player's direction is managed in the CameraController script:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class CameraController : MonoBehaviour
 {
     public Transform target;
 
     public float rotateSpeed;
 
     public Transform pivot;
 
     public Vector3 offset;
 
     public bool useOffsetValues;
     
     public bool invertY;
 
     void Start()
     {
         if (!useOffsetValues)
         {
             offset = target.position - transform.position;
         }
 
         pivot.transform.position = target.transform.position;
         pivot.transform.parent = target.transform;
 
         Cursor.lockState = CursorLockMode.Locked;
     }
 
     void LateUpdate()
     {
         //Gets the X position of the mouse & rotate the target
         float horizontal = Input.GetAxis("Mouse X") * rotateSpeed;
         target.Rotate(0, horizontal, 0);
 
         //Moves the camera based on the current rotation of the target & the original offset
         float desiredYAngle = target.eulerAngles.y;
         float desiredXAngle = pivot.eulerAngles.x;
         Quaternion rotation = Quaternion.Euler(desiredXAngle, desiredYAngle, 0);
         transform.position = target.position - (rotation * offset);
 
         if(transform.position.y < target.position.y)
         {
             transform.position = new Vector3(transform.position.x, target.position.y - .5f, transform.position.z);
         }
 
         transform.LookAt(target);
     }
 }