1. Hide the specific page’s header and footer.
2. To do this, edit the page. Then, go to Page Settings and turn on the “Disable Header” and “Disable Footer” options.
3. If necessary, hide your page title section and make the page layout Fullwidth
4. Add a Row Layout block with a Minimum Height of 100vh – find this under the “Advanced” tab in the block settings.
5. Use a video as the Row Layout’s background
6. Set the Row Layout block’s content alignment to the middle

Here’s a screen recording of how it worked on my website – https://share.getcloudapp.com/9ZuL2QL6.