jQuery and Mootools on the same page

I am working on a Contao site that is supposed to be upgraded from 2.11.6 to 3.5.40 because the provider will soon force a PHP upgrade from 5.6 to 7.3. The upgraded site should look and feel like the old site.

I have already done the Contao upgrade, and all pages look fine except the home page, which uses two extensions:

• MenuMatic 0.68.3 for the main navigation (all pages use this)
• FlexSlider 1.4.3 directly underneath the menu (only on the home page)

MenuMatic uses Mootools, FlexSlider uses jQuery. The two extensions don't seem to work together. If I enable only Mootools, the menu works (hovering over one of the top elements drops down the submenu); if I add the FlexSlider content element with jQuery, the slider works, but not the menu dropdown. I haven't found a slider that runs with Mootools on contao 3.5.

MenuMatic injects these scripts on the page: see attachment1
Attachment 326

This is what I tried:

• use a pure CSS menu: works on a simple html page, not on the Contao home page – no dropdown
• insert jQuery.noConflict() in the FlexSlider script that appears in the page html
• wrapping flexslider.js with jQuery(document).ready(function( $ ) { ... });

flexslider.js with noConflict: see attachment2
Attachment 327

Can you help?