PCで専ブラじゃなくChrome等のブラウザの場合は拡張機能 User JavaScript and CSS
https://chromewebstore.google.com/detail/user-javascript-and-css/nbhcbdghjpllgmfilhnhkllmkecfmpld
をブラウザに追加して URL pattern: https://*.5ch.net に対して以下のような
JavaScriptコードを入れてやればできた

window.addEventListener('load', function() {
const title = document.title;
const board = location.pathname.replace(/^.*\/(\w+)\/\d+\/.*$/g, "$1");
// if (board == "news") {
if (/最強のスクリプト対策/.test(title)) {
const articles = document.querySelectorAll(".thread>article");
for (var i = 1; i < articles.length; i++) {
var article = articles[i];
var ng = true;
var postuesrname = article.querySelector(".postusername").innerText;
if (/(\(\S+\))(\(\S+?\))/.test(postuesrname))
ng = RegExp.$1.indexOf(RegExp.$2) < 0;
if (ng)
article.style.display = "none";
}
}
});