Hello baldarch,
It is not clear, how do you try to add galleries. Do you use several shortcodes or insert galleries with help of Gallery Template?
Please provide an URL to a page with gallery.
“It also trashed my custom vertical menu and navigation settings.” – the gallery functional can’t affect to these changes. Probably, it is a plugins conflict. Please provide a screenshot of what was before and after gallery activation, so that we could see what do you mean.
Please contact our support with detailed description of your problem, we will try to help you.
https://support.bestwebsoft.com
Kind regards,
BestWebSoft