The Content by Label macro allows you to filter by parent. Have you had a look at that? The only downside is that it does display the title of the content that uses the specific label.
Otherwise, I have created a feature request to be able to restrict the Labels List Macro further that you're welcome to follow and vote on:
Hi my Community friends! For those who don't know me, I'm a product marketer on the Confluence Cloud team - nice to meet you! For those of you who do, you know that I've been all up in your Co...
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