ThemeSwitcher Pro

Note: This code is run on the setup_theme hook so WordPress query functions cannot be used. However, ThemeSwitcher Pro provides some alternatives, such as:

tsp_get_post_id() : To get the post id.

tsp_get_taxonomy_slug() : To get the taxonomy slug.

tsp_is_taxonomy( $taxonomy_slug ) : Check if the request is from a taxonomy.

tsp_get_term() : To get the current term name.

tsp_is_front_page(): Check if the request is from a front page.

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Some of the code examples:
NOTE: In order for code snippets to run reliably, they must be placed in a plugin rather than a theme.

Demo example A: Switch to theme if viewing a category archive page.

/**
 *  Switch to theme if front page.
**/
TSP_Manager::register(
	'twentytwentyone',
	function () {
		return tsp_is_front_page();
	},
	1
);

Demo example B: Switch to theme if viewing a category archive page.

/**
 *  Switch to theme if viewing a category archive page.
**/
TSP_Manager::register(
	'twentytwentytwo',
	function () {
		return tsp_is_tax( 'category' );
	},
	1
);

Demo example C: Switch to a custom theme if viewing a post with post ID.

/**
 * Switch to a custom theme if viewing a post with post ID.
**/
$post_id_from_settings = 1; // Change value to your desired post ID.
TSP_Manager::register(
	'twentytwentythree',
	function () use ( $post_id_from_settings ) {
		return ( $post_id_from_settings === tsp_get_post_id() ) ? true : false;
	},
	1
);

Demo example D: Switch to a custom theme based on post date.

/**
 * Switch to a custom theme if viewing a post with post ID.
**/
$post_id_from_settings = 1; // Change value to your desired post ID.
TSP_Manager::register(
	'twentytwentythree',
	function () use ( $post_id_from_settings ) {
		return ( get_the_date( 'Y-m-d', $post_id ) > date('Y-m-d') ) ? true : false;
	},
	1
);