Thanks! That's much better than screenshots. Truth only exists in source code.
The short answer is that you have to either move the <script> to the end of your document (at least after the bullet list), or add an attribute data-external to it, e.g.,
<script src="https://cdn.jsdelivr.net/npm/@xiee/utils/js/tabsets.min.js" defer data-external="1"></script>
I don't have time to explain the underlying reason. Basically you need to make the JS execute after the bullet list has been loaded on the page.
BTW, I wouldn't recommend using both R Markdown's built-in tabsets and my tabset solution in the same document. You'd better choose only one method.