StringChanger.cs

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

public class ScoreChanger : MonoBehaviour {
  TMP_Text tmp;
  StringChanger stringChanger = new StringChanger();
  float timer;

  int score = 0;

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

  void Update(){
    timer += Time.deltaTime;
    if((int)timer % 2 == 0){
      score++;
    }

    stringChanger.UpdateString(tmp, nameof(score), score);
  }
}

public class StringChanger {

  Dictionary<string, int> prevIntValues = new Dictionary<string, int>();
  Dictionary<string, float> prevFloatValues = new Dictionary<string, float>();

  public void UpdateString(TMP_Text tmp, string name, int value, string format = null){
    if(!prevIntValues.ContainsKey(name) || prevIntValues[name] != value){
      prevIntValues[name] = value;
      if(!string.IsNullOrEmpty(format)){
        tmp.text = string.Format(format, value);
      }else{
        tmp.text = value.ToString();
      }
    }
  }

  public void UpdateString(TMP_Text tmp, string name, float value, string format = null){
    if(!prevFloatValues.ContainsKey(name) || prevFloatValues[name] != value){
      prevFloatValues[name] = value;
      if(!string.IsNullOrEmpty(format)){
        tmp.text = string.Format(format, value);
      }else{
        tmp.text = value.ToString();
      }
    }
  }

}