JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<select id="etapa_id">
  <option value="1">Valor 1</option>
  <option value="2">Valor 2</option>
  <option value="3">Valor 3</option>
  <option value="4">Valor 4</option>
  <option value="5">Valor 5</option>
</select><br><br>

<button class="setval" data-val="1">Setar Valor 1</button><br>
<button class="setval" data-val="2">Setar Valor 2</button><br>
<button class="setval" data-val="3">Setar Valor 3</button><br>
<button class="setval" data-val="4">Setar Valor 4</button><br>
<button class="setval" data-val="5">Setar Valor 5</button><br>

JavaScript

$(document).on('click', '.setval', function(event){
	var etapa_id = $(this).data('val');
  
  $('#etapa_id').val(etapa_id);
});