Going to try the penguins-eggs method you posted. I would love to be able to turn a virtual box environment into an installable medium to make my own version of debian with all my gnome tweaks.
I would also love a solution that doesn’t require booting into the OS first. So that I can take a root dir and turn it into a bootable iso. I tried a bunch of old tutorials for making a boot.iso and linking it into mkisofs with -b but it never worked.
I am willing to learn/use any free tooling. Not picky at all.