So there's at least the two of us doing it this way. Syncthing is an absolutely fantastic tool.
Threema Libre
"F-Droid - Complete independence from Google services"
https://threema.com/en/download/threema-private
One-time purchase. With the built-in option to see your parents' faces. Or not.
The desktop app is currently in beta and offers multiple-device support on Windows, Macintosh and Linux (flatpak).
This is not to take anything away from any of the other options mentioned here (some of which I also use).
Why should Snaps be considered a greater risk to the stability of a Debian system than any of the other packaging formats?
porkbun > cloudflare
I've had a quick look at the FAQs. There it specifically says that the Logseq user is "the king of the data" and that Logseq "works directly with plain-text like Markdown and Org mode".
If true, synchronisation with Syncthing should Just work™ on all platforms that Logseq is available for, except iOS.
I am syncing a whole lot more than just dotfiles and have done so for years. Admittedly, I am running an always-on-instance (multiple, in fact…). Syncthing hasn't put a foot wrong in over a decade.
I am donating a small amount to the project every month and would like to encourage others to do the same.