Did you look at Pelican? I share the frustration with much of Hugo’s infrastructure: the template language is buggy and inscrutable, and the plugin architecture wanting.
I ended up with Hugo, but I considered Pelican. It uses standard Jinja templates, which I find much more rational (but it might just be me) and I recall there were plugins for a lot of things, including different source formats. The code is written in Python, so that even if there isn’t a plugin for a format you need, there probably is a Python library for it and it should be relatively easy to make it a plugin.
Crap, now I want to switch to Pelican…



I suggest one of the many wonderful one-page templates available on GitHub, Codeberg, et. al. GitHub has a whole topic on them at https://github.com/topics/single-page-site. You pick one that matches your requirements and that looks good to you, change the text, and serve.