I found issue on Elementor Github and I see that people want to make a background slider transitions and slideshow. It is possible to do this with some premium plugins, but people don’t really want to pay for this feature alone. Therefore, I decided to tell how you can do this with just the installed Elementor and without using third-party plugins.
In order to make the background from the slider for free, only using Elementor, you should to do the following steps.
Create Some Input Content

Create some internal content for which you want to make a background slider. It is also important to place content to the inner section with padding.
Add Elementor Image Carousel

The background slider will consist of such an element as a “Image Carousel”. Use the same parameters as shown in the picture above.
Set z-index

Set z-index for content and carousel. Carousel should be below content. You can use 10 for content and 5 for carousel.
Image Carousel Positioning

Position should be absolute.
Section Overflow

And the final step – set the main section overflow to hidden.
Final structure for Background Slider

The final structure of our slider should be like that.
Elementor provides fast work on frontend, but if you want to make quick work in the wp-admin panel, then perhaps Admin Quick Panel would be interested to you.
If you have ideas on how to make this method better or you just want to write your opinion, do it in the comments below.