What's missing in my code ! 10 Dollars for the person who solve this problem :)

I want to send emails to the assignees + admins for every action Here is my User Model

<?php

namespace App\Models;

use App\Models\UserAlert;
use App\Support\HasAdvancedFilter;
use App\Traits\HasTeam;
use Carbon\Carbon;
use DateTimeInterface;
use Hash;
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Contracts\Translation\HasLocalePreference;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;

class User extends Authenticatable implements HasLocalePreference, MustVerifyEmail
{
    use HasFactory, HasAdvancedFilter, Notifiable, HasTeam, SoftDeletes;

    public $table = 'users';

    protected $casts = [
        'is_approved' => 'boolean',
    ];

    protected $hidden = [
        'remember_token',
        'password',
    ];

    protected $dates = [
        'email_verified_at',
        'created_at',
        'updated_at',
        'deleted_at',
    ];

    protected $fillable = [
        'name',
        'email',
        'password',
        'locale',
        'team_id',
        'is_approved',
    ];

    public $orderable = [
        'id',
        'name',
        'email',
        'email_verified_at',
        'locale',
        'team.name',
        'is_approved',
    ];

    public $filterable = [
        'id',
        'name',
        'email',
        'email_verified_at',
        'roles.title',
        'locale',
        'team.name',
    ];

    public function getIsAdminAttribute()
    {
        return $this->roles()->where('title', 'Admin')->exists();
    }

    public function scopeAdmins()
    {
        return $this->whereHas('roles', fn ($q) => $q->where('title', 'Admin'));
    }

    public function alerts()
    {
        return $this->belongsToMany(UserAlert::class)->withPivot('seen_at');
    }

    public function preferredLocale()
    {
        return $this->locale;
    }

    protected function serializeDate(DateTimeInterface $date)
    {
        return $date->format('Y-m-d H:i:s');
    }

    public function getEmailVerifiedAtAttribute($value)
    {
        return $value ? Carbon::createFromFormat('Y-m-d H:i:s', $value)->format(config('project.datetime_format')) : null;
    }

    public function setEmailVerifiedAtAttribute($value)
    {
        $this->attributes['email_verified_at'] = $value ? Carbon::createFromFormat(config('project.datetime_format'), $value)->format('Y-m-d H:i:s') : null;
    }

    public function setPasswordAttribute($input)
    {
        if ($input) {
            $this->attributes['password'] = Hash::needsRehash($input) ? Hash::make($input) : $input;
        }
    }

    public function roles()
    {
        return $this->belongsToMany(Role::class);
    }

    public function getCreatedAtAttribute($value)
    {
        return $value ? Carbon::createFromFormat('Y-m-d H:i:s', $value)->format(config('project.datetime_format')) : null;
    }

    public function getUpdatedAtAttribute($value)
    {
        return $value ? Carbon::createFromFormat('Y-m-d H:i:s', $value)->format(config('project.datetime_format')) : null;
    }

    public function getDeletedAtAttribute($value)
    {
        return $value ? Carbon::createFromFormat('Y-m-d H:i:s', $value)->format(config('project.datetime_format')) : null;
    }

    public function team()
    {
        return $this->belongsTo(Team::class);
    }

    
}

Here is my Project Model :-

<?php

namespace App\Models;

use App\Support\HasAdvancedFilter;
use App\Traits\Auditable;
use App\Traits\Tenantable;
use Carbon\Carbon;
use DateTimeInterface;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

class Project extends Model
{
    use HasFactory, HasAdvancedFilter, SoftDeletes, Tenantable, Auditable;

    public $table = 'projects';

    public const STATUES_RADIO = [
        'active' => 'Active',
        'hold'   => 'Hold',
        'closed' => 'Closed',
    ];

    protected $dates = [
        'created_at',
        'start_date',
        'end_date',
        'updated_at',
        'deleted_at',
    ];

    protected $fillable = [
        'name',
        'owner_id',
        'start_date',
        'end_date',
        'statues',
        'team_id',
    ];

    public $orderable = [
        'id',
        'name',
        'owner.name',
        'created_at',
        'start_date',
        'end_date',
        'statues',
        'updated_at',
        'deleted_at',
        'team.name',
    ];

    public $filterable = [
        'id',
        'name',
        'owner.name',
        'created_at',
        'package.name',
        'start_date',
        'end_date',
        'statues',
        'assignee.email',
        'updated_at',
        'deleted_at',
        'team.name',
    ];



    protected function serializeDate(DateTimeInterface $date)
    {
        return $date->format('Y-m-d H:i:s');
    }

    public function owner()
    {
        return $this->belongsTo(User::class);
    }

    public function getCreatedAtAttribute($value)
    {
        return $value ? Carbon::createFromFormat('Y-m-d H:i:s', $value)->format(config('project.datetime_format')) : null;
    }

    public function package()
    {
        return $this->belongsToMany(Package::class);
    }

    public function getStartDateAttribute($value)
    {
        return $value ? Carbon::parse($value)->format(config('project.date_format')) : null;
    }

    public function setStartDateAttribute($value)
    {
        $this->attributes['start_date'] = $value ? Carbon::createFromFormat(config('project.date_format'), $value)->format('Y-m-d') : null;
    }

    public function getEndDateAttribute($value)
    {
        return $value ? Carbon::parse($value)->format(config('project.date_format')) : null;
    }

    public function setEndDateAttribute($value)
    {
        $this->attributes['end_date'] = $value ? Carbon::createFromFormat(config('project.date_format'), $value)->format('Y-m-d') : null;
    }

    public function getStatuesLabelAttribute($value)
    {
        return static::STATUES_RADIO[$this->statues] ?? null;
    }

    public  function assignee()
    {
        return $this->belongsToMany(User::class);
    }

    public function getUpdatedAtAttribute($value)
    {
        return $value ? Carbon::createFromFormat('Y-m-d H:i:s', $value)->format(config('project.datetime_format')) : null;
    }

    public function getDeletedAtAttribute($value)
    {
        return $value ? Carbon::createFromFormat('Y-m-d H:i:s', $value)->format(config('project.datetime_format')) : null;
    }

    public function team()
    {
        return $this->belongsTo(Team::class);
    }
}

Here is my ProjectObserver :-

<?php

namespace App\Observers;

use App\Models\Project;
use App\Models\User;
use App\Notifications\DataChangeEmailNotification;
use Notification;

class ProjectObserver
{
    public function created(Project $project): void
    {
        $payload = [
            'action' => 'created',
            'model'  => sprintf('%s#%s', get_class($project), $project->id),
            'reason' => auth()->user(),
        ];

        $admins = User::admins()->get();

        Notification::send($admins, new DataChangeEmailNotification($payload));
    }

    public function updated(Project $project): void
    {
        $payload = [
            'action' => 'updated',
            'model'  => sprintf('%s#%s', get_class($project), $project->id),
            'reason' => auth()->user(),
        ];

        $admins = User::admins()->get();

        Notification::send($admins, new DataChangeEmailNotification($payload));
    }

    public function deleted(Project $project): void
    {
        $payload = [
            'action' => 'deleted',
            'model'  => sprintf('%s#%s', get_class($project), $project->id),
            'reason' => auth()->user(),
        ];

        $admins = User::admins()->get();

        Notification::send($admins, new DataChangeEmailNotification($payload));
    }
}

here my migration :-

  Schema::create('project_user', function (Blueprint $table) {
            $table->unsignedBigInteger('project_id');
            $table->foreign('project_id', 'project_id_fk_9107252')->references('id')->on('projects')->onDelete('cascade');
            $table->unsignedBigInteger('user_id');
            $table->foreign('user_id', 'user_id_fk_9107252')->references('id')->on('users')->onDelete('cascade');
        });

How to send emails to Admin + Assignee ???