a.montask/app/Models/Tasks.php

<?php

namespace App\Models;

use Illuminate\Console\View\Components\Task;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\Facades\DB;


class Tasks extends Model
{
    use HasFactory;

    protected $table = 'tasks';

//    protected $primaryKey = 'id'; // چون جدول UUID داره
//    public $incrementing = false;
//    protected $keyType = 'int';

    protected $fillable = [
        'task_id',
        'name',
        'description',
        'workspace_slug',
        'assignees',
        'start_date',
        'target_date',
        'priority',
        'description_html',
        'completed_at',
        'project',
        'workspace',
        'state',
        'json',
        'created_at',
        'updated_at',
        'deleted_at',
        'created_by',
        'updated_by',
        'deleted_by',
        'parent',

    ];

    public function users()
    {
//        return $this->belongsToMany(User::class, 'pivot_tasks', 'task_id', 'user_id');
        return $this->belongsToMany(
            User::class,
            'pivot_tasks',
            'task_id',
            'user_id',
            'task_id',
            'plain_id',
        );
    }

    public function pivotTask()
    {
        return DB::table('pivot_tasks')
            ->where('task_id', $this->task_id);
    }

}