When I view your site there is no whitespace where the title would have been. I can see you have removed it with display: none
so this does not leave empty whitespace.
An educated guess tells me you may be wanting to remove the whitespace between the header and the main content?
This can be done by editing the page template and giving the main group block – the one that is wrapping the page title – a top margin of zero. The downside of this is that will also zero out the top margin on other pages that do have a visible page title. An alternative might be to create a new template, name it something like Page No Title, and remove the Post Title block from that template. Then in the page that is set as your front-page you will be able to select this new template instead of the default page template.