disable-advanced-mode.user.js

// ==UserScript==
// @name         maud force single
// @namespace    https://us.hinaloe.net/
// @version      0.1
// @description  Force disable advanced mode
// @author       Hina
// @match        https://mstdn.maud.io/web/*
// @grant        none
// @run-at document-start
// ==/UserScript==

(function() {
    'use strict';
    const el = document.getElementById('initial-state')
    if(el) {
        const initialState = JSON.parse(el.textContent)
        initialState.meta.advanced_layout = false
        el.textContent = JSON.stringify(initialState)
    }
})();