You are welcome
!
With respect to ventoy, well it is open source, so you can decide for yourself
.
Nevertheless here is what is my opinion: Why does it "work", when direct methods do not?
Ventoy boots its own boot manager, based on grub as far as I remember to have read. This means that most systems of the computer are fully initialized afterwards.
Ventoy uses the boot manager of the ISO image only if necessary, unavoidable, or selected by the user. Normally it analyzes the intended booting method, e.g. by finding out what boots the ISO, and then analyzing and executing the configuration file as boot manager itself. Its creator spends a lot of time in learning about different operating systems and flavors thereof. Thus he can even "inject" information to the system or kernel, e.g. to use given files on its own device (stick, sd-card, ssd, or the like) as usable storage space within the destination os.
You can select, what is actually used for booting: ventoy's version of grub, a (standard) grub provided with the ventoy device or even the ISO's boot mechanism.
Me, I think this is a very formidable tool!