Being marked as available in MacOS 10.15, while last Mojave is 10.14.6, means that crash is normal. You have to wrap the call to the API by @available(OSX 10.15)

@mksmurali most common cause is that the class in IB of the viewController is not set to the one where you try to drag and drop. Check in Identity Inspector. You may also have to do a Clean Build Folder and possibly restart Xcode.

Do you confirm that you get         "this is the player name that was transferred (playerName)"       printed twice ? So the key is to analyse WHO calls it. The called function cannot tell us.

Launch screen ?. Do you mean initial VC screen or launch storyboard (I would not understand why launch storyboard has an impact here).

That's logical, it is the same, just put in a long logical test what was in a series of if else. The main difference is a question of readability.