You can select a location on what post type you are going to display in the custom field.
Display on a Single Post
Add a lazy block with the name “Embed Video” with no content controls and inspector controls. And use a theme template for the output method, then create a file under “/wp-content/themes/blockbase-child/blocks/lazyblock-embed-video/block.php”.
Note: You can use whatever type of output method you would like to use.
Display the custom field to a specific single post by using the custom block you created (Embed Video block).
Display on a Page
Add a lazy block with the name “Custom Post Video” with no content controls and inspector controls. And use a theme template for the output method, then create a file under “/wp-content/themes/blockbase-child/blocks/lazyblock-custom-post-video/block.php”.
Note: You can use whatever type of output method you like to use.
Add this custom code and save. Note: You can change it according to your style and needs.