As others have pointed out, there are good reasons not to do that.
However, rolling your own SSG should take a few hours. You can look at features and CHANGELOGs of others, and decide if any of those sound neat to implement in your SSG, but to be honest, you can probably build something with a markdown converter or a liquid template library and `make` in about as much time as many SSGs require you to configure.
Want a specific theme from a well known SSG? If the license allows, port it.
I've been using hugo for a while and I'm running into similar issues. Considered jekyll and many others, but I've kind of resigned myself to spending a couple of evenings this week just writing my own very basic tool, probably based on a Makefile and some standard command line tools, and maybe a small amount of custom code that won't change under me (it'll be in my private repos).
The argument for a SSG is to make it possible to e.g. update your header or footer without this turning into a week process of changing thousands of blogposts.
> Build failures of my static site, which has maybe a few dozen posts...
> Suggestions for alternatives welcome...
Plain HTML? No build process needed.