RedditSupressAppNotification.user.js

// ==UserScript==
// @name         Reddit Remove App Notification
// @namespace    http://tampermonkey.net/
// @version      0.3
// @description  try to take over the world!
// @author       You
// @match        https://www.reddit.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=reddit.com
// @grant        none
// ==/UserScript==


(async function() {
    'use strict';

    let style = document.createElement("style")
    style.innerText = `
    body.scroll-disabled {
       position: initial !important;
       overflow: auto !important;
    }

    .NavFrame > div:not([class]) {
        display:none;
    }

    body {
        overflow: auto !important;
        pointer-events: initial !important;
    }

    shreddit-experience-tree {
        display: none;
    }

    shreddit-async-loader[paint-group="xpromo"] {
        display: none;
    }
    `

    document.body.appendChild(style);
})();