I really like this approach. I make similar distinctions between posts meant for email, posts that should appear in RSS, posts that belong on the homepage, and posts that should live under /archive without appearing on the homepage.

I use Substack for email distribution too. For the website side, I built an open-source blogging platform called Jant (https://jant.me) around these needs: posts appear on the homepage by default, posts marked as Featured are included in RSS, and posts can also be unlisted. It also syncs everything to GitHub as Markdown, in a repo that works as a complete Hugo site.