How to update a scoreboard? | SimpleScoreboard

Hello everyone, this is my first post, so excuse me for any mistake I make, I also clarify that I don't know how to speak English so I'm using google translate, once I have clarified all that I proceed with the reason for the publication.

I started learning how to develop plugins about 2 weeks ago and I wanted to create a scoreboard, so I found a post from a user who left a code called SimpleScoreboard, I proceed to leave the code below:

Code:

public class SimpleScoreboard {

    private Scoreboard scoreboard;

    private String title;
    private Map<String, Integer> scores;
    private List<Team> teams;

    public SimpleScoreboard(String title) {
        this.scoreboard = Bukkit.getScoreboardManager().getNewScoreboard();
        this.title = title;
        this.scores = Maps.newLinkedHashMap();
        this.teams = Lists.newArrayList();
    }

    public void blankLine() {
        add(" ");
    }

    public void add(String text) {
        add(text, null);
    }

    public void add(String text, Integer score) {
        Preconditions.checkArgument(text.length() < 48, "text cannot be over 48 characters in length");
        text = fixDuplicates(text);
        scores.put(text, score);
    }

    private String fixDuplicates(String text) {
        while (scores.containsKey(text)) {
            text += "§r";
        }
        if (text.length() > 48) {
            text = text.substring(0, 47);
        }
        return text;
    }

    private Map.Entry<Team, String> createTeam(String text) {
        String result = "";
        if (text.length() <= 16) {
            return new AbstractMap.SimpleEntry<>(null, text);
        }
        Team team = scoreboard.registerNewTeam("text-" + scoreboard.getTeams().size());
        Iterator<String> iterator = Splitter.fixedLength(16).split(text).iterator();
        team.setPrefix(iterator.next());
        result = iterator.next();
        if (text.length() > 32) {
            team.setSuffix(iterator.next());
        }
        teams.add(team);
        return new AbstractMap.SimpleEntry<>(team, result);
    }

    public void build() {
        Objective obj = scoreboard.registerNewObjective((title.length() > 16 ? title.substring(0, 15) : title),
                "dummy");
        obj.setDisplayName(title);
        obj.setDisplaySlot(DisplaySlot.SIDEBAR);

        int index = scores.size();

        for (Map.Entry<String, Integer> text : scores.entrySet()) {
            Map.Entry<Team, String> team = createTeam(text.getKey());
            Integer score = text.getValue() != null ? text.getValue() : index;
            String value = team.getValue();
            if (team.getKey() != null) {
                team.getKey().addEntry(value);
            }
            obj.getScore(value).setScore(score);
            index -= 1;
        }
    }

    public void reset() {
        title = null;
        scores.clear();
        for (Team t : teams) {
            t.unregister();
        }
        teams.clear();
    }

    public Scoreboard getScoreboard() {
        return scoreboard;
    }

    public void send(Player... onlinePlayers) {
        for (Player p : onlinePlayers) {
            p.setScoreboard(scoreboard);
        }
    }

}

And the code I use to create the scoreboard is:

Code:

import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerJoinEvent;

import es.miplugin.SimpleScoreboard;
import me.clip.placeholderapi.PlaceholderAPI;

public class Scoreboard implements Listener{
  
    @EventHandler
    public void onScore(PlayerJoinEvent event) {
        Player player = event.getPlayer();
        String prefix = "%luckperms_prefix%";
        prefix = PlaceholderAPI.setPlaceholders(event.getPlayer(), prefix);
      
        SimpleScoreboard scoreboard = new SimpleScoreboard("§f\u16CB§e§l Title §f\u16CB");
        scoreboard.add("§f§m---------§e§m---------");
        scoreboard.add("§f§m---------§e§m---------");
        scoreboard.add("§e\u00BB§fNombre");
        scoreboard.add("§e"+player.getDisplayName());
        scoreboard.blankLine();
        scoreboard.add("§e\u00BB§fRango");
        scoreboard.add(prefix);
        scoreboard.blankLine();
        scoreboard.add("§e\u00BB§fJugadores");
        scoreboard.add("§e"+Bukkit.getServer().getOnlinePlayers().size());
        scoreboard.blankLine();
        scoreboard.add("§7§otitle.xyz");
        scoreboard.add("§e§m---------§f§m---------");
        scoreboard.build();
        scoreboard.send(player);
    }
}

The code works perfectly and marks everything I want, but my problem is that I don't know how to update it, that is, I don't know how to create a method to update it, I tried several codes that I found in the forums, but none of them worked and if I come back to create the marker once I restore it, I have flickering problems, I hope someone can help me please, I clarify that the codes are not mine since I am new to development in general, first of all thank you very much.

PD: I would appreciate if you could help me to create a flashless update method, first of all thank you very much and sorry for the inconvenience.
I also clarify that the only thing I want to update is the prefix, which I get from luckperms and the number of players online.