I have the iPhone 15 and CarPlay works fine in my FK8. I have a USB-A to USB-C cable plugged into the USB outlet. Plug in the phone and CarPlay starts up.
It might be your cable that isn't working, OP. I find that a brand new cable will work 3-6 months on average before needing to be replaced. I think it's generally from cold climates that cause the wires to deteriorate inside the cable. The colder it is and the more you bend the cable, the shorter that time frame ends up being.. the cable will work in most cases still but not with the car.
I have given up on wired connectivity lol its too annoying.
I have an iPhone 15 Pro Max in an Otterbox Defender case that is held on securely via a Nikumotors mount + Proclip magsafe holder + Apple magsafe charger combo. Automatically connects to bluetooth for sound (mostly use Spotify) and I just use Google maps or whatever on the phone screen when GPS is needed.
I use my iPhone 15 Pro on my '21 CTR. My wife uses her iPhone 15 Pro Max on her '24 Civic.
Neither of us has had a problem recently. I say 'recently' because I had problems on my CTR a couple years ago. Those problems have gone away. The only thing that's changed has been newer IOS releases.
When I was having problems I tried a few different cables. None seemed to make things any better.
The current one is the one that came with the iPhone. My wife's Civic has wireless CarPlay.
Thanks - my iOS is up to date - the local Honda tech said they’re having problems with the iPhone 15 on all their models. If I can’t get it to work he said to bring it in.