I understand that if i am building a watchOS app using SwiftUI, there is no storyboard file involved. Hence, the user interface can be created all programatically. Similarly, can watchOS with Objective C be created without StoryBoards ?
No you cannot:
Read this: https://stackoverflow.com/questions/33401704/can-i-programmatically-create-wkinterfacebutton
Note also, in the options when creating a new WatchOS project, if you select objectiveC, you can only use storyboard.