JSFiddle - React, Tailwind, and code Playground
HTML
<div contenteditable>
<ol>
<li>line #1</li>
<li>line #2</li>
<ol>
<li>line #3</li>
<li>line #4</li>
<li>line #5</li>
</ol>
</ol>
</div>JavaScript
const li1 = document.querySelector("li");
const li4 = document.querySelector("ol > ol > li + li");
getSelection().setBaseAndExtent(li1.firstChild, 0, li4.firstChild, li4.firstChild.length);
document.execCommand("insertUnorderedList");