How to prepare multi dual boot?

Install ventoy

yay -S ventoy-bin 

run GUI

/opt/ventoy/VentoyGUI.x86_64

in options set Pathition sheme to GPT.

Then just copy ISOs to USB drive.

you can use

sync

to make sure that usb can be unmounted and ejected.

Command

watch -n 1 "grep Dirty /proc/meminfo"

is useful to check progress.