I agree with most other members that anything you do will make it shiny and not match the flat appearance. Furthermore any kind of polish will tend to get into the gaps around the button, making an impossible to clean up mess. If you try to tape it off you will end up with a shiny spot on the button.
The best bet is to just live with it.
If that is not acceptable, replace it. Unfortunately, I suspect that button top is part of a larger module and that the entire $$$ module would have to be replaced. You might be able to find a used one at a wrecking yard. Be sure to get the service manual for instructions on how to get the module out and back in without breaking anything.
Last ditch effort would be to polish both buttons to match. Plastic polishes exist; do not use metal polishes on plastic as the metal polish may contain chemicals that attack plastic. To get a clean result you will probably still need to remove the module before working on the buttons.
BTW: what use is that OPTION button? It seems to just jump to menu items that are the same as what I can get at with the MENU button.
1998 Case 580L series 2
1999 Mazda Protege ES
2000 Dodge Ram 4x4 2500 Cummins
2007 Kestrel Talon SL with HED-3 wheels
2013 Subaru Crosstrek XV
2017 Polaris XP900 with tracks and full cab.
2018 Alfa Romeo Giulia Ti Q4 sport everything
Past vehicles of note
1994 WhiteGMC single axle dump
1971 Norton Commando
1964 Jaguar E-type convertible