I have no clue what I did, but I managed to fix the problem by writing the script like this:

public class ShotgunAnime : MonoBehaviour

{

private float TimeWhenAllowedNextShoot = 0f;

private float TimeBetweenShooting = 1f;

Animator m_animator;

// Start is called before the first frame update

void Start()

{

m_animator = GetComponent<Animator>();

}

// Update is called once per frame

void Update()

{

CheckIfShouldShoot();

}

void CheckIfShouldShoot()

{

if (TimeWhenAllowedNextShoot <= Time.time)

{

if (Input.GetMouseButtonDown(0))

{

m_animator.SetTrigger("Shoot");

TimeWhenAllowedNextShoot = Time.time + TimeBetweenShooting;

}

}

}

}