The only new car I’m aware of that should not monitor you would be the Slate pickup. Early in their development they mentioned this as a feature, but they haven’t brought it up in a while. So something to double check.

I purposely still use Google on one of my PCs. I’m of the opinion that having a limited presence on their algorithms is better than trying to be invisible. So, Google knows I like Magic the Gathering & DnD.

Steam has free voice chat as well. Hardly open source though.