Inheritable boolean field for product entity

Shopware 6 (English)
1

I’m trying to add an inheritable boolean field to the product entity with a switch field setting on the admin page, but I couln’t find a proper way to do this. I could use custom fields but they’re not inheritable, which is the main reason why I’m using this approach.
I tried following the tutorials to add a custom entity, an entity extension and an entity extension definition, but I couldn’t find any resources on how to implement this setting on the admin page.
this is my extension class:

class CustomizationExtension extends EntityExtension
{

    public const EXTENSION_NAME = 'customizationExtension';

    public function extendFields(FieldCollection $collection): void
    {
        
        $collection->add(
            (new OneToOneAssociationField(self::EXTENSION_NAME, 'id', 'product_id', CustomizationExtensionDefinition::class, true))
            //->addFlags(new Inherited())
        );
    }

    public function getDefinitionClass(): string
    {
        return ProductDefinition::class;
    }
}

and my entity definition:

class CustomizationExtensionDefinition extends EntityDefinition
{
    public const ENTITY_NAME = 'maxim_customization_extension';

    public function getEntityName(): string
    {
        return self::ENTITY_NAME;
    }

    public function getEntityClass():string {

        return ProductCustomizationEntity::class;
    }

    public function getCollectionClass():string {
        return ProductCustomizationCollection::class;

    }

    protected function defineFields(): FieldCollection
    { 
        return new FieldCollection([
            (new IdField('id', 'id'))->addFlags(new Required(), new PrimaryKey()),
            new FkField('product_id', 'productId', ProductDefinition::class),
            //(new StringField('customization_text', 'customizationString')),
            (new BoolField('is_customizable', 'isCustomizable'))
            //->addFlags(new Inherited()),
,
            new OneToOneAssociationField('product', 'product_id', 'id', ProductDefinition::class, false),
 
            /*
            new ParentFkField(self::class),
            new ParentAssociationField(self::class, 'id'),
            new ChildrenAssociationField(self::class), */
        ]);
    }
    
    public function isInheritanceAware(): bool
    {
       // return true;
       return false;
    }
}

and the entity:

class ProductCustomizationEntity extends Entity
{
    use EntityIdTrait;


    public const ENTITY_NAME = 'maxim_customization_extension';

    public function getEntityName(): string
    {
        return self::ENTITY_NAME;
    }



   public function getEntityClass(): string
    {
        return ExampleEntity::class;
    } 

    protected function defineFields(): FieldCollection
    { 
        return new FieldCollection([
            (new IdField('id', 'id'))->addFlags(new Required(), new PrimaryKey()),
            new FkField('product_id', 'productId', ProductDefinition::class),
            //(new StringField('customization_text', 'customizationString')),
            (new BoolField('is_customizable', 'isCustomizable'))
            //->addFlags(new Inherited()),
            ,
            new CreatedAtField(),
            new UpdatedAtField(),
            new OneToOneAssociationField('product', 'product_id', 'id', ProductDefinition::class, false),

         /*  new ParentFkField(self::class),
            new ParentAssociationField(Product::class, 'product_id'),
            new ChildrenAssociationField(self::class),  */
        ]);
    }
    
    public function isInheritanceAware(): bool
    {
        //return true;
        return false;
    }

}

I also tried the lines that are commented out.

And finally the product detail form on the admin page:

<sw-switch-field                    
                    :label="'asdf'"                    
                    v-model="product.isCustomizable"
                />

The switch field shows up but nothing happens when I save it. I tried writing v-model=„product.customizationExtension.isCustomizable“ but I get the error that it’s undefined.
Is it a problem with the extension definition or do I have to further extend the admin form? How do I make the field inheritable for product variations?