After spending a couple hours trying to figure out how to change the speed of this particular slider script in this theme, I feel like I need to post the solution here for anybody that might be having the same trouble.
How to change the Autoplay Speed in anythingslider / anything-slider:
Find and edit this file:
themes/une_boutique/js/template.min.js
And change this part of the code:
anything-slider-autoplay > .wpb_column > .wpb_wrapper").owlCarousel({navigation:!0,singleItem:!0,autoPlay:7e3,
To whatever you want the speed to be (10 seconds would be 1e4):
anything-slider-autoplay > .wpb_column > .wpb_wrapper").owlCarousel({navigation:!0,singleItem:!0,autoPlay:1e4,
Just putting this out here, hoping it helps anybody in my situation.