FadeText.cs

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

// source: https://www.youtube.com/watch?v=WiUUW9RSa5Y
public class FadeText : MonoBehaviour
{
    private readonly float fadeTime = 1f;
    private TMP_Text fadeAwayText;
    private float alphaValue;
    private readonly float FPS = 30f;
    private float da;

    private void Awake()
    {
        fadeAwayText = GetComponent<TMP_Text>();
    }

    void Start()
    {
        da = fadeTime / FPS;
        alphaValue = 1f;
        fadeAwayText.color = new Color(fadeAwayText.color.r, fadeAwayText.color.g, fadeAwayText.color.b, alphaValue);
        InvokeRepeating(nameof(ReduceOpacity), 1.5f, 1f / FPS);
    }

    private void ReduceOpacity()
    {
        if (alphaValue <= 0f) return;
        alphaValue -= da;
        fadeAwayText.color = new Color(fadeAwayText.color.r, fadeAwayText.color.g, fadeAwayText.color.b, alphaValue);
    }
}