til/system/creating-a-multiboot-usb.md

You can prepare multiboot usb with ventoy. On arch, install ventoy-bin.

Then install ventoy to your usb with

sudo /opt/ventoy/Ventoy2Disk.sh -i /dev/sdc

By default it will format /dev/sdc1 with ext4. You can change it if you like:

sudo mkntfs --fast --label Ventoy /dev/sdc1

From now on, you can basically copy iso files to your usb stick.