@Codeberg-AsGithubAlt To build upon the settings suggested by @jmooring in that post, I have created an example that you can clone and test by running hugo locally. See instructions on one of the example pages.
Relevant commit to make a site navigable offline: Make the site navigable with offline HTML (268e5cf7) · Commits · hugo-mwe / Hugo MWE · GitLab
The example also attempts to fix the issue with links back to homepage when looking at the content offline.
As he and I have suggested earlier, how well your site works offline depends on the theme design (the theme decides not just for looks but also how the links to various pages, sections, etc. work).
This example works well (from the brief testing I did), both online and offline.
In this GIF, you can see me clicking through all the links; you can see the file:// protocol in the address bar.
What’s next? You will certainly need to read up on the Hugo Docs as this is your first time using this tool.