RAID is not a backup. I’m not sure about syncthing, does that count as backup? Have you tried restoring from it?
I managed to put my family on wireguard. I said ‘install this and come to me when you are done’, I finished the setup and told them ‘the key icon must always be visible’. I don’t know how, but it worked 🤷
I sync them to out local fileserver using syncthing and recently started using immich (since it supports custom libraries now)