I use Firefox (LibreWolf with Mozilla sync) on multiple devices. To have my tabs, extensions and history easy available I use Mozilla for syncing that data.
Would it be possible to just use a generic sync service like rsync or something, to sync the profile folders and every file in it?
Or would that break or corrupt data?
You can self host Firefox sync although it’s a pain. Or you can sync only bookmarks using an extension like xbrowsersync or floccus. Otherwise using the official Firefox sync is the best option.