JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="en">

  <head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/css/bootstrap.min.css">
  </head>

  <body>
    <hr>
  
    <div class="container text-left ">
      <table class="table table-bordered table-hover ">
        <thead style=" border-width: 5px">
          <tr>
            <th class="col-fit">fdfffffffffffffffffffffffffffffffffffffffff</th>
            <th class="col-fit">adfsfds</th>
            <th class="col-fit">celfdla</th>
            <th class="col-fit">cella</th>
            <th class="col-fit">cella</th>
            <th id="piros">piros</th>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td>cella</td>
            <td>fgg</td>
            <td>cella</td>
          </tr>
          <tr>
            <td>cella</td>
            <td>cella</td>
            <td>cella</td>
          </tr>
          <tr>
            <td>cella</td>
            <td>cellf</td>
            <td>cella</td>
          </tr>
          <tr>
            <td>cella</td>
            <td colspan="2">cellakinyujtoz</td>
          </tr>
        </tbody>
      </table>
    </div>
    
    <hr>
    
    <div class="container text-left ">
      <table class="table table-bordered table-hover table-fit">
        <thead style=" border-width: 5px">
          <tr>
            <th>fdfffffffffffffffffffffffffffffffffffffffff</th>
            <th>adfsfds</th>
            <th>celfdla</th>
            <th>cella</th>
            <th>cella</th>
            <th id="piros">piros</th>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td>cella</td>
            <td>fgg</td>
            <td>cella</td>
          </tr>
          <tr>
            <td>cella</td>
            <td>cella</td>
            <td>cella</td>
          </tr>
          <tr>
            <td>cella</td>
            <td>cellf</td>
            <td>cella</td>
          </tr>
          <tr>
       ...

CSS

.table .col-fit {
  width: 0;
}

.table.table-fit {
  width: auto;
}