\Illuminate\Database\Eloquent\Relations\Relation::macro('getMorphAlias', function ($value) {
    if (is_object($value)) {
        $value = get_class($value);
    }
    
    $morphMap = \Illuminate\Database\Eloquent\Relations\Relation::morphMap();

    $flipMorphed = array_flip($morphMap);

    $alias = $flipMorphed[$value] ?? throw new \RuntimeException("Please add class $value to \Illuminate\Database\Eloquent\Relations\Relation::enforceMorphMap");

    return $alias;
});

$id = 1;
$class = \App\Models\Organization::class;
$classAlias = Relation::getMorphedAlias($class);

ImageCover::create([
    'coverable_id' => $id,
    'coverable_type' => $classAlias,
]);

    public function register()
    {
        \Illuminate\Database\Eloquent\Relations\Relation::macro('getMorphedAlias', function ($value) {
            $morphMap = \Illuminate\Database\Eloquent\Relations\Relation::morphMap();

            $flipMorphed = array_flip($morphMap);

            $alias = $flipMorphed[$value] ?? null;

            return $alias;
        });

        // ImageCover
        \Illuminate\Database\Eloquent\Relations\Relation::enforceMorphMap([
            \App\Models\ImageCover::CONVERABLE_ORGANIZATION => \App\Models\Organization::class,
        ]);
    }