Select filter in QueryBuilder for nested relationship

RelationshipConstraint::make('client')
    ->icon('hugeicons-user-multiple')
    ->multiple()
    ->selectable(
        IsRelatedToOperator::make()
            ->titleAttribute('public_name')
            ->label(__('invoice::main.list.client'))
            ->searchable()
            ->preload()
            ->multiple()
    ),

public function subscription()
{
    return $this->morphOne(config('soulbscription.models.subscription'), 'subscriber')->ofMany('started_at', 'MAX');
}

public function plan()
{
    return $this->belongsTo(config('soulbscription.models.plan'));
}