Target-info currently returns a list of children, however it does not expose the index of the child that can be used by --child.
I've created a PR (fox-it/acquire#240) for Dissect Acquire to include --list-children so that during data acquisition on a hypervisor it can be used to pass the correct values to --child without resorting to hypervisor specific commands.
Ideally target-query supports this same syntax and the index of the child is also returned by target-info.