Engine revving while on park (P) and neutral (N)

Since this is not a US market car, I do not have any access to specific information about it. Personally, I would bet on a vacuum leak, or intake manifold gasket leak. Also, if it has an idle air control valve, that could be bad as well.

To check the intake manifold gasket (as well as vacuum lines), start the engine. Then simply spray some carburetor cleaner around the intake and vacuum lines. A sudden change in idle speed indicates a leak. https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge - look at this guide, it has some good information too.

To test the idle air control valve, check this guide: https://www.2carpros.com/articles/how-a-idle-air-control-valve-works

Youtube video on testing the IAC valve - https://www.youtube.com/watch?v=GEGItKeg970

Start there and let us know what you find.