for DuckDuckGo, this works for me (on the development console of chromium):

imagetiles = document.querySelectorAll('.tile--img')
for (i of imagetiles){
  if (i.querySelector('a').href.includes('pinterest')) {
    i.setAttribute('style', 'display: none')
  }
}

I just couldn't figure out why some still evade detection and, more importantly, why my monkey script containing this code doesn't work.

Just hoping we can help each other.