I've had the same experience. Debian 11 Vanilla install, nothing special. Ran the pre-install script as Andrew mentions above. The only thing I do differently is in /debian/resources/config.sh I manually set some values like DB password, admin password etc.
After that I kick off the /debian/install.sh script, go get some coffee and come back to a fully configured system.
Do you have any error logs we can look at? Which version of Debian are you using?