YOu must wait for your game to fully load.
// ==UserScript==
// @name SeaSploit ESP
// @namespace http://tampermonkey.net/
// @version 0.1
// @description YOu must wait for your game to fully load.
// @author Lemons
// @match *://krunker.io/*
// @run-at document-start
// @grant none
// ==/UserScript==
fetch(document.URL).then(res => res.text()).then(res => {
res = res.replace(/if\(!tmpObj.inView\)continue;/, '');
document.open();
document.write(res);
document.close();
});