Otter Block in Post

<div class="otterframe">
<iframe src="https://otter.ai/s/OKUtWbXvTdODm7XlnnSnPg">
</iframe>
</div>

Then you can also unpublish the page (in order to not have it indexed or visible in the site) and then use the post's "preview" link (from the post editor) as the URL for external site embedding.

<style>
    /* .modal{max-width:60vw} */
    /* .post-wrap{height:100vh} */
    .post-nav,.post-title,.post-meta{display:none}
    .container-wrap-modal{padding:0}
    section.post{margin:0}
    body.post-template article.post{padding:0}
    div.contentarea{height:50px}
</style>