Hey there adstyle,
Thanks for reaching out to Apple Support Communities. I understand CarPlay is missing from Settings on your iPhone. I’ll be happy to help with this.
Do you have any content or privacy restrictions enabled with ScreenTime on your iPhone? If so, go to Settings > Screen Time > Content & Privacy Restrictions and turn these features off, restart your iPhone and see if the issue is resolved:
Restart your iPhone, iPad, or iPod touch
If you don’t have any content or privacy restrictions enabled, go to Settings > Screen Time > Content & Privacy Restrictions and turn it on. Tap on Allowed Apps, toggle CarPlay Off, wait 30 seconds, and toggle CarPlay back on. Turn Content & Privacy Restrictions back off. Restart your iPhone and see if the CarPlay option is available.
Let me know if this helps.