Found working example in this forum with PHP call for reusable block:
$reuse_block = get_post(123); // Where 123 is the post id
$reuse_block_content = apply_filters('the_content', $reuse_block->post_content);
echo $reuse_block_content;
This code works with lazyblock too, display content only once (even if lzb still placed on the page), so I’m good with it, but maybe you know another lzb-way ??