How to create different kinds of Mac Windows using File menu commands?

You can add menu items to the main menu using commands. This takes a CommandsBuilder closure that builds a Commands.

Using a CommandGroup, you can replace the "New Window" menu item added by WindowGroups by default.

struct OpenWindowCommands: Commands {
    @Environment(\.openWindow) var open
    var body: some Commands {
        CommandGroup(replacing: .newItem) { // .newItem is where the New Window/Open menu items are placed
            Button("New Anagrams Window") {
                open(id: "Anagrams")
            }
            Button("New Wordle Window") {
                open(id: "Wordle")
            }
            Button("New Crosswords Window") {
                open(id: "Crosswords")
            }
        }
    }
}

Then you can have 3 WindowGroups:

WindowGroup(id: "Anagrams") {
    Text("Anagrams Window")
}.commands { OpenWindowCommands() }

WindowGroup(id: "Wordle") {
    Text("Wordle")
}
.commands { OpenWindowCommands() }

WindowGroup(id: "Crosswords") {
    Text("Crosswords")
}
.commands { OpenWindowCommands() }

Output:

If anagrams, wordles, and crosswords are represented by custom structs you wrote, you can use the [init(for:content:)]3 initialiser instead.

/*
Assuming you have

struct Anagram: Codable, Hashable {
    ...
}
*/

WindowGroup(for: Anagram.self) { $anagram in
    // ...
}

// the "open" calls should be changed to use the value: parameter
open(value: Anagram(...))

If the anagrams, wordles and crosswords are files (documents) that your app supports opening and writing, consider using a DocumentGroup instead.