Hi,
i do a simple 1:1 backup with offlineimap, which saves the mails in plain text files (similar what you get when look at the source in thunderbird).
These files are backed up regularily with restic.
Both backups are running automatic, and on multiple machines…
Same here, works fine for me. The only hitch dor me was that sending from one of domains to another of mine counts towards outgoing mails. Changed the recipient afterwards, everything’s shiny now!
I do prefer having a local copy of my backups (and therefore i use rclone), but afaik restic does support b2 directly…
My way of using paperless-ngx includes an automatic export to plain pdf-files which are synced via syncthing.
Everything is accessible with a normal filesystem and over the keepass-gui…