facebook_requests_with_posts_only.user.js

// ==UserScript==
// @name facebook_requests_with_posts_only
// @match https://www.facebook.com/*
// @version 1
// @grant none
// ==/UserScript==

const key = (event) => ["f", "ƒ"].includes(event.key) && event.ctrlKey && event.altKey;

let filtering = false;
document.addEventListener(
  "keydown",
  event =>
    {
      if (event.target instanceof HTMLInputElement) {return;}
      if (!key(event)) {return;}
      filtering = !filtering;
      for (request of document.querySelector(".x1k70j0n:nth-of-type(2)").children) {
        if (!request.textContent.includes("Preview")) {
          request.style.display = filtering ? "none" : "";
        }
      }
    },
  true
);