If the car didn't have car play I'd refuse to take it as it's clearly faulty. I can't remember the last time I had a rental car without those features.
plug in usb
press "ok"
method, no matter what the manufacturer.
Sometimes I have to press the "carplay" icon on the screen, but it's quite rare
The bigger problem is that some cars are USB-C and some are USB-A. I have both cables in my bag though.
I don't bother with wireless car play as my phone always needs charging anyway.
I have to select CarPlay on the Honda I bought last year so it can't be that rare.
all the big touch screens don't really support multitouch and the volume of navigation versus music is different/deafening/unconfigurable and the waze carplay app is garbage
i.e., I always just use my phone on a holder + connect via the car's bluetooth since I'd rather have one good device/screen with proper audio since bluetooth works much better sadly...
Can't wait for the post-mortem analysis in 10 years.
Sorry that is not something i am going to cry for GM over