the issue is if they have customised an existing theme you won’t be able to just download it and use it.
Theme is not important, They are using Elementor to design pages, as for what themes they are using it hard to say because they are only showing used css inline.
you can look at the source code for ideas, look for style.css and what folder this is in as well as comments in the file itself.
you can also use tools like: [https://builtwith.com/](https://builtwith.com/)
the issue is if they have customised an existing theme you won’t be able to just download it and use it.
Theme is not important, They are using Elementor to design pages, as for what themes they are using it hard to say because they are only showing used css inline.