Obsidian is one of my favorite apps. I use it to build Knowledge Bases, write articles, take notes, and learn as much as I can. It's pretty versatile. It works well, but I don't pay for a premium subscription. Instead, I will either email my notes in MD (Markdown) format to myself, transfer them directly from the device via USB, or sync them using Syncthing inside Termux and a special folder on my desktop computer. But that seems like a lot of work to merely sync some files. So, I found two excellent alternatives that let you self-host your syncing without an insane workaround like mine.