Remember/maintain navbar scroll position between pages ( Javacript )

Question

I have a vertical navbar on the left side of my page like this:

$active = basename($_SERVER['PHP_SELF'], ".php");

echo '<ul id="navbar">
        <li id="page1" class="'; echo ($active == 'page1') ? 'active' : ''; echo '" onclick="navbarScrollSetItem(this.id)">
          <a href="page1.php">Page 1</a>
        </li>
        <li id="page2" class="'; echo ($active == 'page2') ? 'active' : ''; echo '" onclick="navbarScrollSetItem(this.id)">
          <a href="page2.php">Page 2</a>
        </li>
        <li id="page3" class="'; echo ($active == 'page3') ? 'active' : ''; echo '" onclick="navbarScrollSetItem(this.id)">
          <a href="page3.php">Page 3</a>
        </li>

        ...

I've set the overflow to scroll and I need it to remember/maintain the scrollbar position between pages, so I've tried this:

function navbarScrollSetItem(navbarLiId) {
  let navbar = document.getElementById('navbar');
  let navbarLi = document.getElementById(navbarLiId);
  navbar.scrollTop = (navbarLi.offsetTop);
  localStorage.setItem('scrollPos', navbar.scrollTop);
  console.log('navbarLiId: ' + navbarLiId + ' scrollPos: ' + navbar.scrollTop);
}

And on load I've tried this:

function navbarScrollGetItem() {
  let navbar = document.getElementById('navbar');
  let scrollPos = localStorage.getItem('scrollPos');
  navbar.scrollTop = scrollPos;
}

But unfortunately it's not working, it's doing basically the same as this:

navbar.scrollIntoView({behavior: "auto", block: "start"});

What I really need is for the scrollbar to maintain exactly the same position on the page as if the page was never changed!

Can anyone help me out please?