How to understand entities, save, hasChanged

Thank you for all the pointer thus far! Really appreciated. Really having a hard time understanding entities. I still get an error Call to a member function fill()

PHP Code:

use App\Models\QgisSkiResortModel;
use App\Entities\QgisSkiResortEntity;

class Ski_Controller extends Admin_Controller
{

    public function __construct(){
        parent::__construct();
        $this->QgisSkiResortModel   = new \App\Models\QgisSkiResortModel;
    }

public function qgis_data_update_aa_winter_sports_points_from_file(){
    
        $file = file_get_contents(WRITEPATH.'ski/qgis_data/aa_winter_sports_points.geojson');
        $aa_winter_sports_points = json_decode($file);  // The json_decode() function is used to decode or convert a JSON object to a PHP object.
        
        $i = 0;                 // used to count the number of ski resorts
        $hasChanged = 0;
        $nothingToUpdate = 0;
        
        foreach ($aa_winter_sports_points->features as $aa_winter_sports_point ){
        
            // Convert stdClass object to associative array in php
            // https://stackoverflow.com/questions/34428702/convert-stdclass-object-to-associative-array-in-php
            $data = array($aa_winter_sports_point->properties);
            $new_fill = json_decode(json_encode($data[0]), TRUE);
            
            // find() will return an entity $existing_data.  Works also in findAll();
            $QgisResort = $this->QgisSkiResortModel->find($new_fill['id']);
            
            //get list all permissable attributes that can go into the db
            $attributes = $this->QgisSkiResortModel->allowedFields;
           
            // filter new attributes in the new fill
            $attributes_matching_from_new_fill = array_filter($new_fill, function ($value, $key) use ($attributes) {
                if (in_array($key, $attributes)) {
                  return true;
                }
            }, ARRAY_FILTER_USE_BOTH);
        
 >>> JUST FOR DEBUG           print_r($attributes_matching_from_new_fill);die(); <<<<<<
           
 >> FAILS HERE           $QgisResort->fill($attributes_matching_from_new_fill);

            if ($QgisResort->hasChanged()){
                $hasChanged++;
                $this->QgisSkiResortModel->save($QgisResort);
                echo "changed";
                echo '<br>';
            } else {
                $nothingToUpdate++;
                echo '<pre>';
                echo 'no change';
                echo '<br>';
                echo '</pre>';
            }
            $i++;
        }
        
        //return redirect()->to('/admin/ski/upload_fs_data')
         //   ->with('info', 'There are a total of '.$i.' resorts counted.  </br>Total Updated/New: '.$hasChanged.'<br>Total Unchanged: '.$nothingToUpdate);
    }

} 


The above code still fail at $QgisResort->fill($attributes_matching_from_new_fill); and says "Call to a member function fill() on null", however, when I echo out $attributes_matching_from_new_fill I have the following;

PHP Code:

Array ( 
  [contact:website] => http://www.theboon.net/opas/ 
  [landuse] => winter_sports 
  [name] => 太平山スキー場　オーパス 
  [name:en] => Taiheizan Ski Area Opus 
  [wikidata] => Q11443946 
  [id] => relation/5466186 
)