Write your own. You know what subset of features you care about, only implement what you need how you need it, and don't worry about making it extensible for others. You'll never need to read any documentation or worry about breaking changes when you update it, and you'll know exactly what it is doing.

I wrote my blog's static site generator 10 years ago and I'm still using it. If I want something it doesn't do, I change it. It's still a single-file perl script and it's easier (for me) than any other option.