How do I properly set up a .tooltip background blur effect?

Question

I am trying to utilize a background blur effect on the tooltip to make it readable on hover. My intuition is telling me that the background has a higher Z value than the tooltip. I have tried a few things to try to resolve the blur effect, but nothing seems to change the outcome. If I modified backdrop-filter to just filter: blur, it looks like the tooltip disappears behind the background.

Issue

let btn = document.querySelector("#btn");
let sidebar = document.querySelector(".sidebar");
let searchBtn = document.querySelector(".bx-search");

btn.onclick = function() {
  sidebar.classList.toggle("active");
}
searchBtn.onclick = function() {
  sidebar.classList.toggle("active");
}

{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Comic sans MS", sans-serif;
}

body {
  position: relative;
  min-height: 100vh;
  width: 100%;
  overflow: hidden;
  background: url(achtergrond.jpg);
  background-size: cover;
  background-position: center;
}

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  height: 100%;
  width: 78px;
  padding: 6px 14px;
  background: transparent;
  backdrop-filter: blur(20px);
  border-top-right-radius: 12px;
  border-bottom-right-radius: 12px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 1.1);
  transition: all 0.5s ease;
}

.sidebar.active {
  width: 240px;
}

.sidebar .logo_content .logo {
  color: #fcf4f4;
  display: flex;
  height: 50px;
  width: 100%;
  align-items: center;
  opacity: 0;
  pointer-events: none;
  transition: all 0.5s ease;
}

.sidebar.active .logo_content .logo {
  opacity: 1;
  pointer-events: none;
}

.logo_content .logo i {
  font-size: 34px;
  margin-right: 5px;
}

.logo_content .logo .logo_name {
  font-size: 20px;
  font-weight: 400;
}

.sidebar #btn {
  position: absolute;
  color: #ffffff;
  /*kleur lettertype*/
  left: 50%;
  top: 6px;
  font-size: 20px;
  height: 50px;
  width: 50px;
  margin-top: 10px;
  text-align: center;
  line-height: 50px;
  transform: translateX(-50%);
  border: 2px solid rgb(255, 255, 255, 0.0);
  box-shadow: 0 0 10px rgba(0, 0, 0, 1.0);
  border-radius: 12px;
  transition: 0.5s ease;
}

.sidebar #btn:hover {
  /* border-color:#007bff; */
  border-color: #007bff;
  color: #1d1b31;
  /*kleur lettertype*/
}

.sidebar.active #btn {
  left: 90%;
  transform: translateX(-75%);
}

.sidebar ul {
  margin-top: 55px;
}

.sidebar ul li {
  position: relative;
  height: 50px;
  width: 100%;
  margin: 0%;
  list-style: none;
  line-height: 50px;
  margin: 30px 0;
}

.sidebar ul li .tooltip {
  position: absolute;
  left: 130px;
  /* ruimte tussen balk enpositie*/
  top: 0%;
  transform: translate(-50%, -50%);
  border-radius: 6px;
  height: 35px;
  width: 122px;
  background: transparent;
  line-height: 35px;
  text-align: center;
  box-shadow: 0 5px 10px rgba(0, 0, 0, 1.0);
  backdrop-filter: blur(20px);
  transition: 0s;
  opacity: 0;
  pointer-events: none;
  display: block;
  color: #ff0000;
}

.sidebar.active ul li .tooltip {
  display: none;
}

.sidebar ul li:hover .tooltip {
  transition: all 0.5s ease;
  opacity: 1;
  top: 50%
}

.sidebar ul li input {
  position: absolute;
  height: 100%;
  width: 100%;
  left: 0;
  top: 0;
  border-radius: 12px;
  outline: none;
  border: none;
  background: transparent;
  box-shadow: 0 5px 10px rgba(0, 0, 0, 1.0);
  border: 2px solid rgb(255, 255, 255, 0.0);
  padding-left: 50px;
  font-size: 18px;
  color: #fff;
  transition: all 0.5s ease
}

.sidebar ul li input::placeholder {
  color: #5e5d5d;
}

.sidebar ul li:hover input {
  border-color: #007bff;
}

.sidebar ul li .bx-search {
  position: absolute;
  z-index: 99;
  color: rgb(255, 255, 255);
  font-size: 22px;
  transition: all 0.5s ease
}

.sidebar ul li a {
  color: #fff;
  display: flex;
  align-items: center;
  text-decoration: none;
  transition: all 0.5s ease;
  box-shadow: 0 5px 10px rgba(0, 0, 0, 1.0);
  border: 2px solid rgb(255, 255, 255, 0.0);
  border-radius: 12px;
  white-space: nowrap;
}

.sidebar ul li a:hover {
  border-color: #007bff;
}

.sidebar ul li i {
  height: 50px;
  min-width: 45px;
  border-radius: 12px;
  line-height: 50px;
  text-align: center;
}

.sidebar .links_name {
  opacity: 0;
  pointer-events: none;
  transition: all 0.5s ease;
}

.sidebar.active .links_name {
  opacity: 1;
  pointer-events: auto;
}

.social_media {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
}

.social_media #linked {
  position: absolute;
  left: 50%;
  bottom: 5px;
  transform: translateX(-50%);
  min-width: 50px;
  line-height: 50px;
  font-size: 20px;
  border-radius: 12px;
  color: white;
  text-align: center;
  opacity: 0;
  background: transparent;
  transition: all 0.3s ease;
  box-shadow: 0 5px 10px rgba(0, 0, 0, 1.0);
  border: 2px solid rgb(255, 255, 255, 0.0);
}

.sidebar.active .social_media #linked {
  left: 13.6%;
  opacity: 1;
}


/* linked in effect */

.social_media #linked:hover {
  border-color: #007bff;
}

.social_media #log_out {
  position: absolute;
  left: 50%;
  bottom: 5px;
  transform: translateX(-50%);
  min-width: 50px;
  line-height: 50px;
  font-size: 20px;
  border-radius: 12px;
  color: white;
  text-align: center;
  background: transparent;
  box-shadow: 0 5px 10px rgba(0, 0, 0, 1.0);
  border: 2px solid rgb(255, 255, 255, 0.0);
}

.sidebar.active .social_media #log_out {
  left: 87%
}

.social_media #log_out:hover {
  border-color: #007bff;
}

.home_content {
  position: absolute;
  height: 100%;
  width: calc(100% - 78px);
  left: 78px;
  transition: all 0.5s ease;
}

.home_content .text {
  font-size: 25px;
  font-weight: 500;
  color: #b4b3be;
  margin: 12px;
}

.sidebar.active~.home_content {
  width: calc(100% -240px);
  left: 240px;
}

<link href='https://unpkg.com/[email protected]/css/boxicons.min.css' rel='stylesheet'>
<div class="sidebar">
  <div class="logo_content">
    <div class="logo">
      <i class='bx bxs-graduation'></i>
      <div class="logo_name">My Portfolio</div>
    </div>
    <i class='bx bx-menu' id="btn"></i>
  </div>
  <ul class="nav_list">
    <li>
      <i class='bx bx-search'></i>
      <input type="text" placeholder="Search...">
      <span class="tooltip">Search</span>
    </li>
    <li>
      <a href="#">
        <i class='bx bx-grid-alt'></i>
        <span class="links_name">Dashboard</span>
      </a>
      <span class="tooltip">Dashboard</span>
    </li>
    <li>
      <a href="#">
        <i class='bx bx-user'></i>
        <span class="links_name">User</span>
      </a>
      <span class="tooltip">User</span>
    </li>
    <li>
      <a href="#">
        <i class='bx bx-chat'></i>
        <span class="links_name">Messages</span>
      </a>
      <span class="tooltip">Messages</span>
    </li>
    <li>
      <a href="#">
        <i class='bx bx-pie-chart-alt-2'></i>
        <span class="links_name">Analytics</span>
      </a>
      <span class="tooltip">Analytics</span>
    </li>
    <li>
      <a href="#">
        <i class='bx bx-folder'></i>
        <span class="links_name">File Manager</span>
      </a>
      <span class="tooltip">File Manager</span>
    </li>
    <li>
      <a href="#">
        <i class='bx bx-cart-alt'></i>
        <span class="links_name">Order</span>
      </a>
      <span class="tooltip">Order</span>
    </li>
    <li>
      <a href="#">
        <i class='bx bx-heart'></i>
        <span class="links_name">Saved</span>
      </a>
      <span class="tooltip">Saved</span>
    </li>
    <li>
      <a href="#">
        <i class='bx bx-cog'></i>
        <span class="links_name">Settings</span>
      </a>
      <span class="tooltip">Settings</span>
    </li>
  </ul>
  <div class="social_media">
    <a href="index.html"><i class='bx bxl-linkedin-square' id="linked" ></i></a>
    <a href="index.html">#<i class="bx bx-log-out" id="log_out"></i></a>
  </div>
</div>
<div class="home_content">
  <div class="text"> Header hier</div>
</div>

I tried modifying the blur effect, also tried modifying the Z-value. Neither modifications had any effect on outcome.