Straight from the horses mouth:

https://www.apple.com/legal/privacy/en-ww/

Apple has a privacy policy that is not only easy to understand, but easily organised and with links to more details/etc - often small privacy features have entire white-papers published explaining how they work in detail. And all of it is thoroughly reviewed by third parties and Apple would be screwed (especially in countries that are not the USA) if they lied in their privacy policy.

The key takeaway, though, is this (not my words - copied verbatim from the privacy policy):

You are not required to provide the personal data that we have requested.

The key is Apple always requests access to your data. And, you can simply say no when they ask.

That might mean a feature won’t be available - for example, if I leave my phone at a party… I’ll get a message on my watch alerting me to go back and get it within a minute or so of leaving. That feature requires allowing your devices to track your location. I’m willing to do that, in part because Apple goes to extra lengths to hide the identity of the people they are tracking, but if you’re not then fine with it, then don’t enable the feature. It’s disabled by default.

CarPlay is essentially a HDMI connection. Your car doesn’t get anything except a raw video signal and Apple forces car manufacturers to have their systems audited by a trusted third party which, among other things, will check to make sure the car isn’t doing anything else with the data (such as OCR on the video signal).

When you use CarPlay - it’s your phone that has your texts, contacts, call log, etc. The car doesn’t get any of that. You phone does.

And if you don’t want your phone to know where you are, it’s disabled by default. You don’t have to do turn by turn navigation in CarPlay - turn by turn is disabled by default (because enabling it requires tracking you) and you can just listen to podcasts and you can use a third party podcast app if you don’t want apple to know what podcasts you listen to.