It would be very powerful if we could synchronize our notes to a GitHub repository.
I am sorry but Git (and thus GitHub) is not a sync system but a version control system. The idea of using Git internally has been discussed many times in this forum, and the only thing that stood out is that Git would be rather hard to integrate into Joplin.
On the other hand you can always write a cron job to create JEX exports of your notes periodically, save them in a folder and push them to your Githhub repo.
Are you sure?
logseq.com already uses that.
hope, it can as a editer with blog and githubpages
If you need to post joplin notes to a static blog, you can try joplin-blog cli