Demo code for https://richtabor.com/?p=2351

content-locking-pattern.php

<?php
/**
 * Title: Content-only Test
 * Slug: prefix/content-only-test
 */
?>
<!-- wp:group {"templateLock": "contentOnly", "align":"wide","layout":{"type":"constrained","wideSize":"2000px"}} -->
<div class="wp-block-group alignwide"><!-- wp:columns -->
<div class="wp-block-columns"><!-- wp:column -->
<div class="wp-block-column"><!-- wp:image {"id":231,"sizeSlug":"large","linkDestination":"none"} -->
<figure class="wp-block-image size-large"><img src="https://s.w.org/images/core/5.8/outside-02.jpg" alt="" class="wp-image-231"/></figure>
<!-- /wp:image -->

<!-- wp:group {"style":{"spacing":{"blockGap":"var:preset|spacing|20"}},"layout":{"type":"flex","orientation":"vertical"}} -->
<div class="wp-block-group"><!-- wp:heading {"fontSize":"large"} -->
<h2 class="has-large-font-size"><strong>Project 2</strong></h2>
<!-- /wp:heading -->

<!-- wp:paragraph {"fontSize":"small"} -->
<p class="has-small-font-size">A tiny description of this project.</p>
<!-- /wp:paragraph --></div>
<!-- /wp:group --></div>
<!-- /wp:column -->

<!-- wp:column -->
<div class="wp-block-column"><!-- wp:spacer -->
<div style="height:100px" aria-hidden="true" class="wp-block-spacer"></div>
<!-- /wp:spacer -->

<!-- wp:group {"style":{"spacing":{"blockGap":"var:preset|spacing|20"}},"layout":{"type":"flex","orientation":"vertical"}} -->
<div class="wp-block-group"><!-- wp:heading {"fontSize":"large"} -->
<h2 class="has-large-font-size"><strong>Project 1</strong></h2>
<!-- /wp:heading -->

<!-- wp:paragraph {"fontSize":"small"} -->
<p class="has-small-font-size">A tiny description of this project.</p>
<!-- /wp:paragraph --></div>
<!-- /wp:group -->

<!-- wp:image {"id":232,"sizeSlug":"large","linkDestination":"none"} -->
<figure class="wp-block-image size-large"><img src="https://s.w.org/images/core/5.8/outside-02.jpg" alt="" class="wp-image-232"/></figure>
<!-- /wp:image --></div>
<!-- /wp:column --></div>
<!-- /wp:columns --></div>
<!-- /wp:group -->