Simplest approach to mailing list management for a blog?

I've restarted a personal blog (https://jamesgill.net). No niche, no target audience--yet. Just a lot of writing to head that direction. I'd like to set up a simple mailing list and signup. I'm familiar with big players like ConvertKit, MailChimp, etc. What's the simplest list management choice for my situation that leaves me with options for future adjustment/change?