dd(CourseBundle::with('courses')->get()->toArray());

        dd(CourseBundle::with('courses')->get()->toArray());

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;

class CourseBundle extends Model
{
    use HasFactory;

    protected $guarded = ['id'];

    public function courses(): BelongsToMany
    {
        return $this->belongsToMany(Course::class, 'course_course_bundles', 'course_bundle_id', 'course_id')
            ->withTimestamps();
    }
}

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;

class CourseBundle extends Model
{
    use HasFactory;

    protected $guarded = ['id'];

    public function courses(): BelongsToMany
    {
        return $this->belongsToMany(Course::class, 'course_course_bundles', 'course_bundle_id', 'course_id')
            ->withTimestamps();
    }
}