You can tell hugo to build from an arbitrary directory of markdown in the config file. Then it’ll just do it’s best. I have done this experimentally on completely un-optimized obsidian vaults for just my own local use. IIRC there are some mandatory frontmatter elements that hugo requires (date, draft status, and/or title? consult the docs) which will prevent a file from appearing at all if they are missing. Depending how vigilant you are with that kind of thing you can get a more or less janky site straight away.
There are also some plugins, bash scripts etc around that will assist in this. In tidying up the files, selecting which ones to publish, mirroring to another directory etc. I have had mixed success personally, but my vaults are sprawling, badly organized and the frontmatter is often a mess which is all on me. Someone who is less/differently negligent would have different luck. I can provide some links to relevant projects if anyone is interested.
don’t delete your post, people wrote things here.