Did you look at Pelican?
I have not, but I will. I may also look at Zola, although it, too, appears at the surface level to be tightly coupled with markdown.
the template language is buggy and inscrutable
It’s just Go templates, which are pretty solid; I’d be surprised by any bugs, unless they’re in the Hugo short codes. The syntax is challenging, even if you’re a Go developer and use it all the time. It’s a bespoke DSL, and a pretty awful one: it’s verbose, obtuse, and makes some common things hard.
Go is my language of choice, but my faith gets shaky whenever I have to use templates.
I’m not a huge fan of Python; despite its popularity, it’s got a lot of problems, not least of which is the whole Python 2/3 fiasco; which, years later, is still plaguing us. However, if I can containerized it so it isn’t constantly breaking in the background when I do a system update, I’m not opposed to using a project written in it. At least it isn’t Node; I won’t let that crap onto any server I admin.
Edit: Zola has the same problem as Hugo.
They’ve certainly proved capable of shooting reporters in the back.