TextMeshPro Colorize characters

using UnityEngine;
using TMPro;
using System.Collections;

[RequireComponent(typeof(TextMeshProUGUI))]
public class TextmeshProColorizer : MonoBehaviour
{
    public TextMeshProUGUI txt;
    public bool animateColors;
    public float animationSpeed;

    [Space(10)]

    [Header("Colors palette")]
    public Color[] colors;

    private string[] _hexStrings;

    private int _hexIndex;
    private int _txtIndex;
    private string _originalTxt;

    private string _coloredText = "";

    private void Start()
    {
        _originalTxt = txt.text;

        //Initialize the _hexStrings array with the number of colors in the palette
        _hexStrings = new string[colors.Length];

        //Populate the _hexStrings array with the hex code for each color in the palette
        for (int i = 0; i < colors.Length; i++)
        {
            _hexStrings[i] = ColorUtility.ToHtmlStringRGB(colors[i]);
        }

        if (!animateColors)
        {
            //Use only ApplyColors() if we don't want to have the colors animated.
            ApplyColors();
        }
        else
        {
            //Use AnimateColors() if we want to have the colors animated.
            StartCoroutine(AnimateColors());
        }
    }

    private void ApplyColors()
    {

        //We iterate over our text string and create a colored text string stored in _coloredText
        for (int i = 0; i < txt.text.Length; i++)
        {
            _coloredText = _coloredText + "<#" + _hexStrings[_hexIndex] + ">" + txt.text[i].ToString() + "</color>";

            //We skip the hex index increment if the character in the txt is a space
            if (txt.text[i] != ' ')
            {
                _hexIndex++;
                if (_hexIndex > _hexStrings.Length - 1)
                    _hexIndex = 0;
            }
        }

        //We assign the colored version of our text to the text field;
        txt.text = _coloredText;
    }

    private IEnumerator AnimateColors()
    {
        ApplyColors();

        yield return new WaitForSeconds(animationSpeed);

        //We offset the hex color index of 1 so the colors will shuffle
        _hexIndex++;
        if (_hexIndex > _hexStrings.Length - 1)
            _hexIndex = 0;

        _coloredText = "";
        txt.text = _originalTxt;

        //We start the animation again
        StartCoroutine(AnimateColors());
    }
}