I had the CarPlay skipping problem and it was getting annoying -- a skip every few minutes, which means (approximately) one skip in each song. Elsewhere on the forum (the thread cited by Bubbajet) I saw the suggestion to switch from wireless CarPlay to wired CarPlay, via the USB port. At first, it didn't work because, even after my iPhone was plugged in, the music was still transmitted via Bluetooth. I had to go into the iPhone's Settings, Bluetooth, find the ID4, touch the info icon, then turn off CarPlay.
This works. No more skips and, to my untrained ear, the music also sounds a bit better. But it is a PITA because I had just gotten used to being able to leave my phone in my pocket and, when I have to plug it in, I am prone to forgetting it when I leave the car.