JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="gallery-list">
    <li data-id="9425"><strong>item 1</strong></li>
    <li data-id="9426"><strong>item 2</strong></li>
    <li data-id="9488"><strong>item 3</strong></li>
    <li data-id="9489"><strong>item 4</strong></li>
    <li data-id="9495"><strong>item 5</strong></li>
    <li data-id="9427"><strong>item 6</strong></li>
</ul>
<ul id="gallery-container" style="display: none;">
    <li data-id="9425">
        <h3 style="display: none;">Item 1</h3>
        <div class="content">Content here</div>
    </li>
    <li data-id="9426">
        <h3 style="display: none;">Item 2</h3>
    </li>
    <li data-id="9488">
        <h3 style="display: none;">Item 3</h3>
    </li>
    <li data-id="9489">
        <h3 style="display: none;">Item 4</h3>
    </li>
    <li data-id="9495">
        <h3 style="display: none;">Item 5</h3>
        <div class="content">Content here</div>
    </li>
    <li data-id="9427">
        <h3 style="display: none;">Item 6</h3>
        <div class="content">Content here</div>
    </li>
</ul>

JavaScript

$(function() {
    $("#gallery-container li[data-id]").each(function() {
        if ($(".content", this).length == 0) {
            $("#gallery-list li[data-id=" + $(this).data("id") + "]").remove();
        }
    });
});

// or like this:

/*
$(function() {
    $("#gallery-container li[data-id]:not(:has(.content))").each(function() {
        $("#gallery-list li[data-id=" + $(this).data("id") + "]").remove();
    });
});
*/