Strange:
Debian 11 Container (LXC) is not showing $OSTYPE via netclient-install.sh
So it says: "This OS is not currently supported via automated install"
Okay, ubuntu container same thing
uname -i would work
root@UbuntuTest1:~# uname -i
x86_64
so if $OSTYPE is not working you should still check uname -i