放在主题的functions.php文件里

/**
 * 古腾堡编辑器禁用自动保存
 * http://www.gmloc.me/120.html
 */
add_filter('block_editor_settings_all', function($settings) {
    $settings['autosaveInterval'] = 99999;
    $settings['localAutosaveInterval'] = 99999;
    return $settings;
});

清除浏览器缓存。