I’ve used both syncthing and recently resilio. My Syno NAS has their own app Synology drive. All three have worked great for me.

Syno ds920+ w/2 16’s & 2 6’s. Use: home docs, pics, and a Plex server.

QNAP ts233 with 2 6tb for “off-site” backup sitting on my desk at work connected to the guest wifi backing up the home docs and pics from the syno.

follow up - i never considered offsite backups for my data. i have a ds920+ that’s got some big drives in it and thats all i need. but after reading this post i considered backup. what i went with was a qnap ts233, a wifi adapter, and 2 6t’s that i had replaced with bigger ones on my syno. My syno is my daily driver and the new qnap sits on my work desk at the office, syncs with the syno, and backs up my photos and docs. Happy with this back up method. Thanks for the great post.

Syno 920+ for me