I sync hundreds of gigs, (if not terabytes at this point) using Syncthing with errors on only one machine (it’s running on 6 devices, including a VM). And those errors are of my own doing, not random Syncthing errors.

It’s surprisingly robust these days, especially for a single-user notes.

I have an indexing job that runs on my server every 30 minutes, saving into a text file (it indexes my media folder, which is about 3TB of movies and TV shows).

Those text files sync to my phone when they’ve changed (so every 30 minutes). They’re always up to date when I open them.

My phone also has jobs to continually sync my photos to home, an ad-hoc folder to my laptop, and about 25 other folder pairs (including NeoBackup) that sync under different conditions, without fail.

I’m currently testing Cherrytree using Sourcherry on Android and it seems to work fine as a single-user solution with Syncthing.