With Kirby 3, I used this model to retrieve content from an external source (specifically Airtable):
https://getkirby.com/docs/guide/virtual-pages/content-from-api#the-page-model
With Kirby 4, I encounter an error related to the public function children().
Referring to the guide’s model format, it states:
Declaration of ReviewsPage::children() must be compatible with Kirby\Cms\Page::children(): Kirby\Cms\Pages.