Maybe we can back up and discuss exactly what your objective/use-case here is.
I still don’t quite understand why you require a Debian based image here. Is there some requirement that only a pure non-container Debian can fulfill?
If it’s simplicity, then Torizon should also fulfill this need. Torizon is also essentially just a boot and rootfs partition with the dts and kernel in a known location (/boot/ostree/torizon-*/). The container is only where your application stack will live. Also if you don’t want to deal with the network forwarding of containers you can just run the container with the same network stack as the host (--net=host).
But if you really do desire a native Debian based image then you can still attempt this. Just keep in mind it will be difficult for us to support you on something that deviates so heavily from both Torizon and our references images.
Best Regards,
Jeremias