Stop Wordpress editor from stripping your HTML when switching between Visual and text editor or while saving. Be sure to test and keep an eye on conflicts with plugins! https://ikreativ.com/stop-wordpress-removing-html/

raw-html.php

// stop wp removing div tags - goes to Functions

function ikreativ_tinymce_fix( $init ) 
{
    // html elements being stripped
    $init['extended_valid_elements'] = 'div[*],article[*]';

    // don't remove line breaks
    $init['remove_linebreaks'] = false; 

    // convert newline characters to BR
    $init['convert_newlines_to_brs'] = true; 

    // don't remove redundant BR
    $init['remove_redundant_brs'] = false;

    // pass back to wordpress
    return $init;
}
add_filter('tiny_mce_before_init', 'ikreativ_tinymce_fix');

In my test this actually removes the entire visual editing toolbar.