Meta Box

I have resolved this by adding a vale to the 'before' key of the first field of each group, like this:

$meta_boxes[] = [
	'title'          => $title = 'Tweets fetching API',
	'id'             => 'settings_admins__breaking_news_api',
	'settings_pages' => ['settings_admins'],
	'tab'            => 'settings_admins__breaking_news_tab',
	'fields'         => [
		[
			'name'              => 'Enable tweets fetching API',
			'id'                => $id = $prefix . 'breaking_news_enable_api',
			'type'              => 'checkbox',
			'label_description' => '<code class="admins-only">' . $id . '',
			'desc'              => 'Check to enable the tweets fetching API • Run now',
			'before'         => '<h3>' . $title . '</h3><hr>',
		],
		[
			...
		],
		[
			...
		],
	],
];

And here's the result:

I find a way to get the $args of an existing custom post type.

I tried first to use the get_post_types() function, but it was always listing the built-in post types even when I pass the '_builtin' => false in the function args like this:

$args = array(
   '_builtin' => false
);
$post_types = get_post_types( $args );

I found that we can use global $wp_post_types like this:
$wp_post_types['custom_post_type_slug']->arg_slug;.

For example:

$wp_post_types['custom_post_type_slug']->labels;
$wp_post_types['custom_post_type_slug']->menu_icon;
$wp_post_types['custom_post_type_slug']->show_in_menu;
...

I just need a way to get the $args of my custom post types. Please help!