A:AnswerYes you can use it, but sometimes had problems with the compability, but if you use the DSX app from Steam, you'll never going to have problems.
A:AnswerJust a wild guess and my opinion but there is a similar question about whether or not it will work with a PS4 (backwards compatibility) and no one knows. But if it does work with a PS4 it might make sense that it would also work with a PC because the Dualshock 4 was PC and Bluetooth capable. That would be cool if they made it compatible with a cell phone which some Xbox controllers can do. Then you could stream games or fly a drone.
A:AnswerNo you can’t it would Be a waist of money you can only use ps4 controllers on ps5 if it’s connected to a usb and you can only play ps4 games not ps5 but if you try what you are saying it won’t work