I've been using for quite a looong time multisystem - maybe less direct than this one - but useful for a newbey;) https://www.pendrivelinux.com/multiboot-create-a-multiboot-usb-from-linux/
. The only problem is the installation script isnt running for quite some time - so I just add the source manually and apt install the application also manually.. . for normal ISO images they work perfectly
I've been using for quite a looong time multisystem - maybe less direct than this one - but useful for a newbey;) https://www.pendrivelinux.com/multiboot-create-a-multiboot-usb-from-linux/
. The only problem is the installation script isnt running for quite some time - so I just add the source manually and apt install the application also manually.. . for normal ISO images they work perfectly