Hides posts in your linked feed that are Promoted or more than 1 week old. To install click the `Raw` button and your userscript extension will take it from there.

fresh_linkedin_feed.user.js

// ==UserScript==
// @name         Fresh Linkedin Feed
// @namespace    http://bigethan.com/
// @version      0.1
// @description  Hide promoted and weeks old content in the linkedin feed
// @author       @bigethan
// @match        https://www.linkedin.com/feed/
// @grant        none
// ==/UserScript==

(function (document) {
  var observer = new MutationObserver(function (mutations, me) {
    // `mutations` is an array of mutations that occurred
    // `me` is the MutationObserver instance
    var oldEls = document
      .querySelectorAll(".feed-shared-actor__sub-description")
      .forEach((el) => {
        if (/Promoted|weeks ago|month/.test(el.innerText)) {
          el.closest("div.relative.ember-view").remove();
        }
      });
  });

  // start observing
  observer.observe(document, {
    childList: true,
    subtree: true,
  });
})(document);