Bootcamp Testimonials Slider w Vanilla Javascript

Set myself a retrospective challenge of making a scalable slide deck via fetch and DOM manipulation in vanilla javascript. I had done a fair amount DOM creation with javascript years ago and I wanted to retrieve those skills.

The slideshow code [courtesy of a developedbyed tutorial - see the README in the repo] could use some refactoring

One question on variables and looped build of the profile cards - Where do I declare the 'createElement' variables? I have them declared prior to the loop but the code seems a bit cumbersome. Any feedback would be appreciated.