There is a lot of integration in the stock display/head unit besides audio, including climate, navigation, vehicle settings, DVD (if you have that option), etc. The basic head unit design has not changed for the 2010-2019 model years. Some of the earlier 2010-2013 base models have a non-nav option with a smaller screen and without the integrated controls that is probably easier to upgrade, but they are not easy to find.
If you want to do something different like integrate Apple CarPlay or Android Auto, most people are doing a tablet screen conversion kit installation. They used to only have 470 versions, but some 460 kits have been popping up lately. These kits have all of the functionality integrated for climate control, etc., and it will plug into factory wiring harnesses (sometimes with a little modification due to Prado/GX harness differences). But it also uses the factory amplifier and speakers, so if you wanted to go this route you are going to have to do additional modifications to change amplification hardware. Also beware that these kits typically come from China or other SE Asia countries and have very mixed histories of customer service and support.
Check out the GXOR facebook page for some of the tablet conversion kit threads. There aren't many on the GX 460 yet but some have been posted there.