Continuing from my earlier reply...
As an alternative to using your iPhone with CarPlay - if you are already seeking a "mirroring" solution to a small tablet - why not actually consider using an iPad? An iPad can run all the Apps and features already used with your iPhone.
An iPad mini offers a 7.9" screen, while other models have larger sized screens.
If you opt for a WiFi+Cellular iPad model*, the iPad benefits from built-in GNSS/GPS positioning functionality - this being desirable for navigation and mapping as precise positioning data is directly available to the iPad, just like your iPhone. Your iPhone can still provide an internet connection to the iPad using the iPhone's hotspot feature if needed - supporting use of online mapping tools such as Apple Maps, Google Maps, Waze etc - without needing to provision the iPad's own Cellular connection.
Share your internet connection from your iPhone - Apple Support
If preferred, you have the flexibility to use the iPad's own Cellular data capabilities:
Set up cellular data service on your iPad Wi-Fi + Cellular model - Apple Support
*Unlike iPhone and WiFi+Cellular models of iPad, WiFi Only models of iPad do not have built-in GNSS/GPS positioning functionality. While it is possible to use some types of external GPS receiver with an iPad, purchase of a WiFi+Cellular iPad is likely to be both more cost effective and simpler to use.
