There's no need to buy a separate device.

Want to use an iPad as a drawing tablet with a PC? There are a number of ways to do it ...

In a pinch for extra screen space on your PC but don't have a second display? Use this simple USB trick to turn your Android ...

I literally have no idea how using your S9 Ultra as a 2nd monitor works, you mention both wired and wirelessly which doesn't help clarify at all. Could I ask you to explain that to us? But at a lower ...