Reply To: Create a landing page.

Yes, you can hide the main menu and the top right button on a specific page with a snippet of ‘Additional CSS’ added in the customizer.

e.g. if the page ID is 29, the CSS would be this:

.page-id-29 #top-info,
.page-id-29 .site-navigation {
    display: none;
}

You can find the relevant page ID from the ‘post=29’ part of the URL in your browser address bar when editing the page e.g. ...wp-admin/post.php?post=29&action=edit