I want to make an app, where a merchant will create custom sections with html code. If I just create a model in Gadget, it won't be good for performance, because that section will trigger extra api query. Am I right? ChatGPT says that I must also create an additional metafield for this purpose, because metafield will be stored on shopify itself. But I don't understand how I can create a metafield for different blocks and shops, a metafield is smth like one instance, yes? Please help in understanding this