I’ve been using logseq with syncthing for sync, across laptop/desktop/Android. Works ok, app can be a little chunky though and sometimes the manualness of coding queries can. E annoying. I have used joplin, trillium, Zim and a few others in the past. Installed silver bullet as a try too but haven’t gotten far into playing with it
Daily backups. Currently using restic on my NixOS servers. To avoid data corruption, I make a zfs snapshot at 2am, and after that restic does a backup of my mutable data dirs both to my local Nas and CloudFlare r3. The Nas backup folder is synced to backblaze nightly as well for a more cold store.