Page template missing in twenty twenty four theme

I am working on a site, with custom Page templates.

My steps:

1. I have a page called “landing1” for which I am creating a custom page template without header and footer
2. I went to Appearance > Templates > clicked + for new template > chose template for Pages in the modal window > selected landing1 as a page > and removed the header + footer > saved the template
3. When I preview this page, it still shows header, footer
4. I also clicked Edit page > Template part > and it doesn’t show me my template for this page I believe should be landing1. Attached screenshot of what I am seeing i.e. default templates, no my created custom template. Want to know what am I missing?