I sync the (strongly) encrypted database throughout my devices with Syncthing and it works flawlessly. I have an old laptop with syncthing running always on to avoid sync conflicts.
Syncthing looks a lot like a "make your own cloud" solution.
I use OwnCloud in a RaspberryPi, instead. But as Moxie Marlinspike famously said: "People don’t want to run their own servers, and never will". (https://moxie.org/2022/01/07/web3-first-impressions.html)
Of course it's not magical : for them to be in sync, you'll then have to have both turned on with Syncthing running at the same time.
But if you have something lying around, like an old laptop, it's trivial to have it running, and maintenance is super low, just keep update it from time to time : I have Syncthing running on a low cost server for multiple years, syncing pictures + documents, and the only issue I ever had was disk space running out once.