Quoted below:

Thank you Rob for posting this on PasteBin: https://pastebin.com/XXyuwkXp

This is a simple fix to the necessary ad spam on YouTube.

To use, follow the instruction below:

Right-click in your toolbar and select “Add page…” or “Add Bookmark…”
Enter “YT AdSkip” for the name
Paste the single-line version of the code below as the URL
Save the button

Now, when you see an ad on YouTube, press the button. It will do what’s needed to entirely skip the ad.

Single-line version to use as the link for your button

javascript:(( ) => { const v = document.querySelector('video'); if (v) { v.currentTime = v.duration; } const b = document.querySelector('button.ytp-ad-skip-button-modern'); if (b) { b.click(); } })();
formatted version for your review
javascript:(( ) => {
  const v = document.querySelector('video');
  if (v) { v.currentTime = v.duration; }
  const b = document.querySelector('button.ytp-ad-skip-button-modern');
    if (b) { b.click(); }
 })();