When you work with me, that is generally not true. I make most sites from scratch, which was called “making a theme” for you a few years ago. This is an advantage of my strategic orientations to use Elementor as a development sub-platform. This means that in that case, I have full control over the elements of the site, including the appearance of the header and footer.
These possibilities are sometimes limited by the inflexibility of plugins whose task is to enable the implementation of some specific functionalities on the site, or by choosing a very specific theme. But if that happens, you will be notified.