Is there anything that can turn your email into a secure personal RSS feed? A feed reader that also includes emails would replace quite a bit of what centralized social media provides.
The opposite approach is to send RSS feeds to your email client, which can be done by rss2email (originally by Aaron Schwartz).
https://github.com/wking/rss2email
I've been using it for a few years and, while the command line interface is a bit awkward, it works fine. Since email clients have the same controls an RSS reader needs (read/unread, folders, etc.) it works fine.
Blogtrottr is a hosted service that does the same thing; I also used them for a few years and was happy with the service. Just moved off because self-hosting was in some ways simpler for me.