Anon from last thread who triggered the fuck out of the spammer with filterposting here to give another pro tip
Add this script to tampermonkey

// ==UserScript==
// @name Refresh on Tab Focus
// @namespace http://tampermonkey.net/
// @version 1.0
// @description Auto-refresh page when you click on its tab
// @match https://boards.4chan.org/*
// @run-at document-end
// ==/UserScript==

window.addEventListener('focus', () => {
location.reload();
});

This auto refreshes your 4chan tab whenever you switch to it. Combined with common auto tab refresh extensions, the spammers deleted posts get removed before you get a chance to see them
BOOM
GET FUCKED LMFAO