I definitely don't have the best or ideal setup, but I keep things pretty simple. My blog's "CMS" under the hood is a single flat directory of markdown files. Each post is a markdown file, and I use Hugo (gohugo.io) to build a static site out of it and statically host it. I don't really use tags or hierarchies, even though Hugo supports it.

My site isn't open source (b/c unfinished content) but in case it's helpful, it's based on this Hugo template project - https://github.com/thesephist/carlisle

Newsletter wise, I can't be super helpful because I roll my own infra through Mailgun, but I think in general the simpler the better, especially in the beginning. Substack seems popular these days.