JSFiddle - React, Tailwind, and code Playground

HTML

<select id="s">
    <option value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
</select>
<button id="btn_2">2</button>
<button id="btn_3">3</button>

JavaScript

//console.clear();

document.getElementById('btn_2').addEventListener('click', function() {
	document.getElementById('s').value = 2;
});