Coding bootcamp testimonials slider using React and Sass

This is my third solution submitted here. I used this one to learn a lot of new things that I wasn't used to. I chose something that I thought was simples so I didn't become stuck in something too hard and difficult. It was challenging enough and I was finally able to pratice some concepts, despite struggling with simples things like hooks on React. There are parts of the code that I spend too much time to finish just searching for a way to do. I know that there's a lot of things to improve, but I finally reached a point that I'm feeling satisfied. After some research I understood better the hook useEffect and could use it to change the states of the component. This way I could prevent the necessity of having to click twice on the button to trigger the change. It took me quite some time to understand how to implement and I still think that I need to pratice other ways to fully learn. And my backgrounds wouldn't show on live site. It took a while for me to figure out that a dot on the background url would stop the problem. Do you have any suggestion that you would like to make? Anything is welcome. Anyway, thanks for reading that.