I have a 2019 RS and I bought a CPLAY2AIR adapter a few months ago on a black Friday special for $100 and it works very good.
cplay2air.com
I plug it into the USB port in my center console storage and my iPhone connects wirelessly with CarPlay.
It took a firmware update to work with the Blazer initially and ever once in a while I had to unplug the adapter and plug it back in to get it to work. I just updated the firmware again recently and the connection from starting the car seems to be better and faster now too.

CPLAY2air wireless adapter for factory CarPlay on CARPLAY2air.com
Connect wirelessly to your factory Carplay in your Audi, VW, Mercedes-Benz, Volvo or Porsche vehicle what was not possible before. Wired Android auto module inside. Convert wired CarPlay connection to the wireless one!

I plug it into the USB port in my center console storage and my iPhone connects wirelessly with CarPlay.
It took a firmware update to work with the Blazer initially and ever once in a while I had to unplug the adapter and plug it back in to get it to work. I just updated the firmware again recently and the connection from starting the car seems to be better and faster now too.