no_lessons_blocks.php

<?php // <- do not copy this line.

/**
 * This will prevent old lessons and lessons created with the course builder to have blocks added.
 */
add_filter(
	'llms_blocks_should_migrate_post',
	function( $ret, $post_id ) {
		return $post_id && 'lesson' === get_post_type( $post_id ) ? false : $ret;
	},
	10,
	2
);
/**
 * It will, prevent lesson's template elements to be directly shown in front via hooks.
 */
add_filter(
	'llms_blocks_is_post_migrated',
	function( $ret, $post_id ) {
		return $post_id && 'lesson' === get_post_type( $post_id ) ? true : $ret;
	},
	10,
	2
);

/**
 * This will unset the block editor template for the lessons created via wp admin Lessons -> Add New:
 * block will not be added directly in the editor.
 */
add_filter(
	'lifterlms_register_post_type_lesson',
	function ( $lesson_type_array ) {
		unset( $lesson_type_array['template'] );
		return $lesson_type_array;
	}
);