Don’t confuse backups with syncing. Although syncthing has a recycle bin to recover deleted and overwritten files, you shouldn’t rely on it for guarding against accidental deletion, file corruption, or ransomware. You want something that will allow you to restore files from a point in time. There’s lots of proper backup tools for this. Borg, Restic, etc. Each has pros and cons. Make sure you test recovery. Also 3-2-1 is 3 copies of data, on at least 2 different systems, and 1 off site.

Static site generators. Jekyll, Hugo, etc. Pick a template, write in markdown.