User Tags Not Working properly in custom HTML blocks

I am custom building a user interface that relies on simulated windows, instead of dropdown menus, for navigating certain areas of a website. While the user tags such as {display_name} and {user_avatar_small} aren’t displaying their values, but instead rendering as bracketed text.

I tried using the shortcode block and the custom HTML block on my page editor, but neither of them display these values appropriately, however when I use the same tags in my Menu links, or in the membership email templates, they work fine.

I was wondering if it was normal for these features to only work on the membership email templates and main navmenu areas.