Long time ago (10+ years) I'd occasionally google something and find an older blog solution post on my own blog. It is hard to maintain both the revelance and the practice to maintain these over the course of life.
I use the sync feature, but its not required. There are several tutorials for using got with a community plugin or an alternative like syncthing.
Its just text after all. Which is the point of using Obsidian.
Paying for sync is like paying to support the software development. Which is worth doing for Obsidian. Plus I find it useful. I am on the older lower rate.