Hi There,
Thank you for writing in, while that is outside the scope of support, I could point you in the right direction with the understanding that it would ultimately be your responsibility to take it from here.
Please navigate to this directory /x/framework/legacy/cranium/headers/views/global/, copy the file _nav-primary.php. Navigate to your child theme and create this directory /x-child/framework/legacy/cranium/headers/views/global/, there paste the _nav-primary.php file that you just copied.
Open/edit that file and look for the line <i class="x-icon-bars" data-x-icon=""></i>, that is the line that output the bars icon.
Hope it helps,
Cheers!