use `firstOrCreate` for `replayViewCount()`

app/Http/Controllers/ScoresController.php

···
                 ->increment('count');
 
             if ($score instanceof ScoreBest) {
-                if (!$score->replayViewCount()->exists()) {
-                    $score->replayViewCount()->create(['play_count' => 0]);
-                }
-
-                $score->replayViewCount()->increment('play_count');
+                $score->replayViewCount()
+                    ->firstOrCreate([], ['play_count' => 0])
+                    ->incrementInstance('play_count');
             }
         }
 

app/Models/ReplayViewCount/Model.php

···
     protected $primaryKey = 'score_id';
 
     public $timestamps = false;
+    public $incrementing = false;
 
     protected static function suffix()
     {