You are absolutely right, just for clarity:

Chromium needs to be > 12 weight-%. If you take 18 w-% Cr and 8 w-% Ni you get an austenitic steel which is (normally) neither magnetic nor able to be hardened.

And if you add 12 w-% Cr, you remove 12 w-% Fe. So formally this is right-ish too…

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…