I use Restic, called from cron, with a password file containing a long randomly generated key.

I back up with Restic to a repository on a different local hard drive (not part of my main RAID array), with --exclude-caches as well as excluding lots of files that can easily be re-generated / re-installed/ re-downloaded (so my backups are focused on important data). I make sure to include all important data including /etc (and also backup the output of dpkg --get-selections as part of my backup). I auto-prune my repository to apply a policy on how far back I keep (de-duplicated) Restic snapshots.

Once the backup completes, my script runs du -s on the backup and emails me if it is unexpectedly too big (e.g. I forgot to exclude some new massive file), otherwise it uses rclone sync to sync the archive from the local disk to Backblaze B2.

I backup my password for B2 (in an encrypted password database) separately, along with the Restic decryption key. Restore procedure is: if the local hard drive is intact, restore with Restic from the last good snapshot on the local repository. If it is also destroyed, rclone sync the archive from Backblaze B2 to local, and then restore from that with Restic.

Postgres databases I do something different (they aren't included in my Restic backups, except for config files): I back them up with pgbackrest to Backblaze B2, with archive_mode on and an archive_command to archive WALs to Backblaze. This allows me to do PITR recovery (back to a point in accordance with my pgbackrest retention policy).

For Docker containers, I create them with docker-compose, and keep the docker-compose.yml so I can easily re-create them. I avoid keeping state in volumes, and instead use volume mounts to a location on the host, and back up the contents for important state (or use PostgreSQL for state instead where the service supports it).