Config

How do accses a file
this is my code and i would like to know how to get players file and change it
i would like to change only the players config for example he dies or gets a kill

PHP:

<?php

declare(strict_types=1);

namespace besher\PlayerStats;

use pocketmine\plugin\PluginBase;
use pocketmine\event\Listener;
use pocketmine\command\Command;
use pocketmine\command\CommandSender;
use pocketmine\utils\Config;
use pocketmine\event\player\PlayerDeathEvent;
use pocketmine\event\player\PlayerJoinEvent;
use pocketmine\Player;

class Main extends PluginBase implements Listener{
    
    public function onEnable(){
        @mkdir($this->getDataFolder() . "stats/");
        $this->getServer()->getPluginManager()->registerEvents($this, $this);
    }
    
    public function onCommand(CommandSender $sender, Command $cmd, String $label, array $args) : bool{
        switch($cmd->getName()){
            case "stats":
                global $reciver;
                $reciver = $this->getServer()->getPlayer($args[0]);
                    $this->profile($sender);
        }
        return true;
    }
    
    public function onJoin(PlayerJoinEvent $e)
    {
        $player = $e->getPlayer();
        $name = $player->getName();
        $this->cfg = new Config($this->getDataFolder() . "stats/" . strtolower($player->getName()), Config::YAML, array(
            "Name" => "$name",
            "Deaths" => 0,
            "Kills" => 0,
            "Jumps" => 0
        ));
        $this->cfg;
    }
    
    public function onDeath(PlayerDeathEvent $e)
    {
        $player = $e->getPlayer();
        $this->cfg->set("Deaths", $this->cfg->get("Deaths") + 1);
        $this->cfg->save();
    }
    
    public function onKill(PlayerDeathEvent $e){
        $cause = $e->getEntity()->getLastDamageCause();
                if($cause instanceof EntityDamageEntityEvent){
                $killer = $cause->getDamager();
                if($killer instanceof Player){
                    $this->cfg->set("Kills", $this->cfg->get("Kills") + 1);
                    $this->cfg->save();
               }
            }
    }
    
    public function profile($player){
        $form = $this->getServer()->getPluginManager()->getPlugin("FormAPI")->createSimpleForm(function (Player $player, int $data = null){
            if($data === null){
                return true;
            }
        });
        $form->setTitle("§l§2YOUR STATS");
        global $reciver;
        $form->setContent("Player Stats: " . $reciver->getName() . "\nDeaths: "
        $form->addButton("Exit");
        $form->sendToPlayer($player);
        return $form;
    }

}


 

Thats already the way, to store the config instances separately, store and retrieve using $this->cfg[$player->getId()]