that landing page can be done without a pagebuilder if you have the HTML / CSS knowledge. If you don’t then a pagebuilder would be the easiest option.
Things such as Navigation, Page Headers, Footers, Sidebars and the Blog or Single posts you can do without the need for Elementor but it really is up to you 🙂
If I create the landing page with HTML and CSS, will I need a child theme for GP premium? What about the appointment booking plugin on the landing page?