Have you tried Syncthing? [1] An open source alternative to Dropbox.
I use a combination of Unison(-gtk) and Foldersync (android) to replicate some quite large data sets between desktop, server, a couple of laptops, and tablet & phone. Keybase and Synthing are definitely on the list of potential replacements for the manual, periodic sync.
How does Syncthing go insofar as replacing a note-taking system (tagging, collaboration, etc)?
Syncthing’s purpose is to ensure that a specific directory remain synchronized across multiple computers and/or mobile devices. It accomplishes this goal with the minimum of fuss, and (in my experience) works better than Dropbox in that it burns fewer CPU cycles and doesn’t crash/hang/nag me to upgrade.
The other devices wouldn't be, and changes would only be done wherever I happened to be, but the cost of evaluating this solution was unfortunately higher than not making any changes. As I say, it's on my list. The suite seems to be quite robust - but given Evernote's primary stated purpose was to ensure none of your data was ever lost (and yet many people have sad stories of data loss) I'm extra-cautious about changing my workflow.
Or that it'll be egregious when it's time? Solution?