How do i get custom fontSizes and theme fontSizes?

Use useSettings() since useSetting() is deprecated. Then, you can specify a further path with custom or theme to state what data you’d like to get: // User-created presets. useSettings(‘typography.fontSizes.custom’); // Theme-defined presets. useSettings(‘typography.fontSizes.theme’); See this WordPress Playground for a working example.

How to render initial posts on page load in a Gutenberg block using the Interactivity API?

You could consider running actions.getPosts on mount via data-wp-init like: <div … data-wp-init=”actions.getPosts”> As per the documentation: This directive runs a callback only when the node is created. You could also consider server-rendering the initial set of posts, like: <div data-wp-watch=”callbacks.renderContent”> <?php $query = new WP_Query( array( … ) ); ?> <?php while( $query->have_posts() ) … Read more