so, deb boot strap, or debbootstrap is involved in many of these tasks you’re talking about, or the docs cover the specific mount commands needed to be used in conjuection with debbootstrap, I found docs for it here: https://wiki.debian.org/Debootstrap

Hope this helps

I went through this too, except I got pissed off and found a fips compliant image running the last version prior to their disk format changes. Gosh that royally pissed me off.

no calls for restic? I use restic and a s3 layer on the other end, be it either backblaze/wasabi/s3/whatever for remote or minio/garage for local object storage. Stuff just works, then I write a systemd unit file to back it up according to whatever schedule I want for both a local target and a remote target. Helps to solve the 3-2-1 backup strategy this way. Good luck!