How can we add Custom ObjectID to algolia index through scout

Hi, I am using laravel scout package. When I import data or Save model, scout save that data with
App\Model::1 Object Id. I want this ObjectId to customize inside toSearchableArray()

public function toSearchableArray(){
return [‘Objectid’ => 1 ];

How can I do that? I tried several ways but no luck
“algolia/scout-extended”: “^1.13”,
“laravel/scout”: “^8.3”,
laravel 8

Override getScoutKey() from model class
public function getScoutKey()
return ‘custom_id’.$this->id;