Comment by mcshicks

Tailscale, ssh and emacsclient in terminal mode makes it pretty easy to access and update notes from different machines without syncing by just say leaving your main laptop on and connected to the Internet and using emacs daemon. If you have sshd running on all the machines you can use tramp to move files around or use git or many other tools. The trickier part is using emacs key bindings on say android. Read only sharing with PDFs works fine. Co editing is impossible :).