I rolled my own because I wanted to use Jinja inside Markdown. This lets me include widgets in the content, and use Python-based constants in the text. For example, when the German minimum wage changes, I change one constant and it triggers a bunch of updates across the website.
I also wanted to control the content-to-website pipeline a little better. The SSG builds pages, but also generates text-to-speech audio for glossary terms, makes some typographic changes, and lints the Markdown for site-specific issues.
I wrote a bit about it here: https://nicolasbouliane.com/projects/ursus
The code is here: https://github.com/All-About-Berlin/ursus/
Try following a few newsletters. I like that Berlin Events Weekly creates a Telegram channel so people can meet and attend events.
For things to do, Mit Vergnügen is pretty good.
Static sites are almost maintenance-free. They cost pennies to host. You work on your content using the tools that you love, if necessary offline. There are many excellent markdown editors and no CMS comes close. Everything is under source control and deploys with a push.
If you're used to text files and command line utilities, static site generators are a no-brainer. You probably shouldn't roll your own though.