In my case, I stuck with markdown and still used frontmatter to add metadata to posts. Since I'm using asp.net core, I can use the markdown library Markdig which supports frontmatter, but I can also just fallback to the name of the markdown file (regex out the date and title), since I don't need much information from metadata. Adding middleware to asp.net core is fairly easy as well, so I can simply create some simple middleware to create static files as requests come through.
The only annoying case I had was how to manage syncing between git or gitlab (I created post retrieval clients for both) and already generated static files. I have a fairly forced method at the moment, where almost every generated file is wiped when a new git commit shows up, but I get to find those solutions myself since it's mine (!).
Definitely agree with the sentiments here. Although, I feel that the fact there's already working products out there makes it less incentivized to do projects like this. The new programmers I know seem to be more interested in doing something new or creating software you can't just get from some SaaS. I guess when I created my first website I didn't have that worry, there was no squarespace or whatever else, so there was the double benefit of creating something both simple and new.