CODE EXAMPLE FOR PHP

wordpress add block from single.php

// GET a post or page with blocks or whatever and print it 
//on your single.php or other wp file 
$reuse_block = get_post( 123 ); // ID of the post
$reuse_block_content = apply_filters( 'the_content', $reuse_block->post_content);
echo $reuse_block_content;