Try Magic Earth, I love it. Very nice car play support, Apple Watch support, traffic news etc. Give it a try

Organic Maps

Have you tried HERE WeGo, previously known as HERE Maps?

The app started live as Nokia Maps (so Finnish) and is now owned by a consortium of German auto makers (for some reason headquartered in the Netherlands).

I don't have an iPhone, but according to the AppStore listing the iOS version should include CarPlay.

I use sygic, it is more work, in ireland i need to look up the post code for everywhere. I have to use a/ c to stop my iPhone overheating but it says gulf of mexico and that was what I wanted. That and it loads on the homescreen.

You could give OsmAnd a try
https://apps.apple.com/us/app/osmand-maps-travel-navigate/id934850257

I will second OsmAnd. You need to use the paid version from the app store to use CarPlay, but personally I really like it, and use it regularly.

Offline maps are important to me, and it'll happily route me even when there is no signal.

The only downside is, it's only as detailed as OSM (which in all honesty, is often better than gmaps. Plus you can easily contribute things that are missing)

£10/y or £40/perpetual for the version that activates CarPlay (and gives you regular offline map downloads, as the free version only gives you 8 before you have to either pay or side load).

And honestly, I'm not that mad that it's chargeable. They make a good free product based on OSM, I don't mind chipping them a tenner.

TomTom Go works best