I was very disappointed to learn that the tire pressure only says if the pressure is going down, but it doesn´t know what is the actual pressure.
I had a Tiguan that indicated the exact pressure from each tire.
Is there an option to add a sensor that detects that?
And I´m not even sure, the infotainment would indicate it.

 

No option for actual reading of pressure. Volvo's system doesn't work that way. It will only let you know if one tire is not matching the others. There are aftermarket solutions, but they don't integrate into the dashboard screen.