Slight update to @mattroberts code for macOS 14:

ContentView()
    .background(WindowAccessor(window: $window))
    .onChange(of: window) { _, newWindow in                    
        if windowFloats {
            newWindow?.level = .floating
        } else {
            newWindow?.level = .normal
        }
     }
     .onChange(of: windowFloats) {                    
         if windowFloats {
             window?.level = .floating
         } else {
             window?.level = .normal
         }
      }

If you just want it to always float you dont need the second onChange(of:)