In my experience it's just exceedingly rare to require this. My insurance company website has a notification thing, and it's actually static. You need to refresh the page, and considering how few and far between notifications are, and how common refreshes are, it works fine.

There's an entire domain of apps where you truly need a front-end. Any desktop-like application. Like Google Sheets, or Figma. Where the user feedback loop is incredibly tight for most operations.