Easy to use AudioManager. Creates an audio source connected to an audio output to enable easy audio mixing.

AudioManager.cs

using System;
using System.Collections.Generic;
using UnityEngine;

public class AudioManager : MonoBehaviour
{
    private static AudioManager _instance;

    public Sound[] sounds;
    private readonly Dictionary<string, Sound> _soundDictionary = new Dictionary<string, Sound>();

    private void Awake()
    {
        if (_instance != null) Destroy(gameObject);
        else
        {
            _instance = this;
            DontDestroyOnLoad(gameObject);
        }

        foreach (var s in sounds)
        {
            s.source = gameObject.AddComponent<AudioSource>();
            s.source.clip = s.clip;
            s.source.loop = s.loop;
            s.source.outputAudioMixerGroup = s.mixerGroup;
            _soundDictionary.Add(s.source.clip.name, s);
        }
    }

    public void Play(string soundName, bool reverse = false)
    {
        var source = FindSound(soundName)?.source;
        if (source == null) return;

        source.pitch = reverse ? -1 : 1;
        source.time = reverse ? source.clip.length - 0.01f : 0f;
        source.Play();
    }

    private Sound FindSound(string soundName)
    {
        try
        {
            return _soundDictionary[soundName];
        }
        catch (Exception)
        {
            Debug.LogError("Sound: " + soundName + " not found!");
            return null;
        }
    }
}

Sound.cs

using System;
using UnityEngine;
using UnityEngine.Audio;

[Serializable]
public class Sound
{
    public AudioClip clip;

    public bool loop;

    public AudioMixerGroup mixerGroup;

    [HideInInspector] public AudioSource source;
}