I had backblaze, and it’s really a bummer they don’t support linux. The closest one I’ve found is Icedrive, but it costs a bit more. I don’t mind paying a bit more though for a FOSS solution (technially not free but yeah). I probably only have 2 TB of actual important stuff but it would be nice to have more for future.
Borg backup to a local NAS I built that serves NextCloud AIO. It’s a personal cloud I connect to over wire guard. Does that count?
https://github.com/nextcloud/all-in-one
https://scottross.sh/posts/backup-your-system-with-borgbackup/
https://github.com/angristan/wireguard-install/blob/master/wireguard-install.sh