Something like this?

I asked a similar question a while back and it doesn't look like anything has changed. You definitely can't do this in SwiftUI, only with UIKit. You will have to manually position the hour and min text labels and set the width of the picker so that the scrolling numbers line up properly.

From the documentation for this modifier: Use an item-based context menu with a container that supports selection, such as a List or Table. I don't think it is possible as there is no current API for selection in custom views as this is what the context menu is looking for.