@hieu - I’m very much not a developer, myself…
Are you looking for help with Git/Github, or are you familiar with that part of the process? There’s a lot to unpack there, so I’d rather know your level of comfort before I walk through the process.
For the Obsidian part, I go to settings and set the ‘New link format’ to ‘Absolute path in vault’ *Disclaimer - some folks don’t like this as much, because the link format is not as clean as wikilinks. It is a standard link format, though, and works across platforms very well.
Then, using the Github app on Android, I can open the repository and navigate the files. The links work in the app like they do in Obsidian. This is the ‘view-only’ interface I mentioned.
I don’t do much editing on mobile, mostly because it’s messy. I’ve edited straight through the Gihub app, and I have Markor installed - it will also work in a pinch. I could not get Git journal to do what I wanted.
Good luck!