Because disk numbers change from system to system or if you change the number of disks in your system, you cannot specify a drive by using a drive number.
Instead, Ventoy must use a vlnk file which is like a shortcut in windows which specifies which disk and path.
So I think you need to make vlnk files and place those on your Ventoy USB drive.
See https://ventoy.net/en/doc_vlnk.html
It is not clear from the documentation how it finds the iso file - i.e. does it search all drives and use the first one it finds (in which case it may not boot the one we want if there are multiple drives with same iso files) or if more than one file with same path is found on more than one drive, does it give a choice of which one to use?
P.S. This is covered in my eBook (PDF) - 'Getting started with Ventoy' ;-)
Instead, Ventoy must use a vlnk file which is like a shortcut in windows which specifies which disk and path.
So I think you need to make vlnk files and place those on your Ventoy USB drive.
See https://ventoy.net/en/doc_vlnk.html
It is not clear from the documentation how it finds the iso file - i.e. does it search all drives and use the first one it finds (in which case it may not boot the one we want if there are multiple drives with same iso files) or if more than one file with same path is found on more than one drive, does it give a choice of which one to use?
P.S. This is covered in my eBook (PDF) - 'Getting started with Ventoy' ;-)