Removing stylesheets issues (wp_dequeue_style) - optimization

Question

I'm having trouble removing (wp_dequeue_style) all the stylesheets loaded in a WP site.
I want to remove all the styles loaded, with the purpose of recreating a new style that can be better controlled and optimized and reduce 68 requests to 1.
But before I get further into this, I'll say a bit about the tools used.
I'm using Wordpress v5.4.1 on a server with Apache 7.2.30. The WP theme is MasterStudy Child and the plugins used are as follows:
Breadcrumb NavXT
BuddyPress
Contact Form 7
GamiPress
GTmetrix for WordPress
WPBakery Page Builder
MasterStudy LMS Learning Management System PRO
MasterStudy LMS
Paid Memberships Pro
Slider Revolution
GDPR Compliance & Cookie Consent
STM Configurations
Transients Manager
UpdraftPlus - Backup/Restore
WooCommerce
WordPress Importer
WP Reset
Query Monitor
I can get a list of all enqueued CSS stylesheets using 3 methods:
1. Chrome Inspector - Network tab
2. Query Monitor
3. The script bellow, used in functions.php of parent theme
function remove_theme_head_styles() {
global $wp_styles;
echo "<h2>Enqueued CSS Stylesheets</h2>";
foreach( $wp_styles->queue as $handle ) :
echo $handle . ", ";
endforeach;
}
add_action( 'wp_enqueue_scripts', 'remove_theme_head_styles', 9000 );
The results are as follows:
Method 1 (Chrome): 68 requests, though some are duplicates
Method 2 (Query Monitor): 66 Styles
Method 3 (php script): 52 results
Next, lets switch from listing all the enqueued CSS files, to removing them with this script
function remove_theme_head_styles() {
global $wp_styles;
foreach( $wp_styles->queue as $handle ) :
wp_dequeue_style( $handle );
wp_deregister_style( $handle );
endforeach;
}
add_action( 'wp_enqueue_scripts', 'remove_theme_head_styles', 9000 );
Let's see what we have now:
Method 2 (Query Monitor): 13 styles - all of them loaded in the footer. 10 of them are coming from the parent theme and the other 3 from the theme's main plugin MasterStudy LMS
Method 1 (chrome): 14 requests, same as QM except for 1 extra font family CSS
Method 3 (php script echo): 0 results
So, maybe we need to change the hook, go further down the hooks order, to also include the stylesheets enqueued in the footer.
Let's try wp_print_footer_scripts with a big number for priority
add_action( 'wp_print_footer_scripts', 'remove_theme_head_styles', 9000 );
The results are:
Method 1 (chrome): 65 requests, WTF? almost all of them have loaded!
Method 2 (Query Monitor): 0 Styles
Method 3 (php script): 0 results - same hook used for listing, wp_print_footer_scripts
And YES the webpage has rendered accordingly, so the Chrome Inspector is not wrong, but this doesn't mean that the other 2 methods have false results. It just means that the CSS files are re-enqueued after the results of methods 2 and 3 are generated
But how is this happening I cannot understand.
I have also tried splitting the removal process into 2 hooks, 1 with wp_enqueue_scripts and another with different hooks like wp_footer and such, but with no success
The 10 'trouble' styles coming from the theme itself, are loaded with this function
themes/masterstudy/inc/custom.php
function stm_module_styles($handle, $style = 'style_1', $deps = array(), $inline_styles = '')
{
$path = get_template_directory_uri() . '/assets/css/vc_modules/' . $handle . '/' . $style . '.css';
$handle = 'stm-' . $handle . '-' . $style;
wp_enqueue_style($handle, $path, $deps, STM_THEME_VERSION, 'all');
if (!empty($inline_styles)) wp_add_inline_style($handle, $inline_styles);
}
Here's an example of using the function above
themes/masterstudy/vc_templates/stm_mailchimp.php
stm_module_styles('mailchimp', 'style_1', array(), $inline_styles);
Obviously, if I comment that line then the CSS won't be loaded, but this is not the approach I want to take to solving the problem.
So, if anyone can offer some help, it would be much appreciated
Thanks for taking the time and reading through this

Answer 1

The below is likely not a great approach, but I recently needed to prevent VC from loading the free version of FontAwesome (I use the pro version in my theme) and no amount of dequeue/deregister would work - the below is the only way I could stop it loading (without editing files outside my theme).
The thing that actually worked, was brutally unsetting the entry in wp_styles.
function hack_dequeue_fa() {
global $wp_styles;
$remove = array(
'vc_font_awesome_5',
'vc_font_awesome_5_shims',
);
foreach($remove as $handle) {
wp_dequeue_style($handle);
wp_deregister_script($handle);
unset($wp_styles->registered[$handle]);
}
}
add_filter( 'wp_enqueue_scripts', 'hack_dequeue_fa', PHP_INT_MAX );