linuxcnc-live-build

[ -x /usr/bin/git ] || sudo apt install git
git clone https://github.com/LinuxCNC/linuxcnc-live-build
cd linuxcnc-live-build
git checkout buster
[ -x /usr/bin/lb ] || sudo apt install live-build
lb config
sudo lb build

Puts the .iso file in images{desktop}