FTFY: 👏 Do 👏 not 👏 buy 👏 smart 👏 stuff 👏connected 👏to 👏the 👏 internet 👏
Nothing wrong with wanting smart stuff, as long as it doesn't send your data. For example, I run all my home automation hardware on a local network that cannot speak to the web, yet I can control everything I want just as the next guy with his fancy Alexa, Google or whatever, but my house doesn't leak as much data.

For cars this is still very difficult to do. The only way we can stop sharing as much data would be if we had legislation that would ban this type of information sharing/data mining. In Europe we tried barking, but we didn't bite. The GDPR is a joke, forcing people to consent to cookies, net result is nothing. They should have banned data mining, fingerprinting and tracking al together, but the tech lobby is way too powerful for that.

Voting with your wallet doesn't work here. People will choose the most convenient option and the other options will eventually start to disappear. Like safety, this needs to be regulated because security and privacy is by definition inconvenient.

It really depends, I would say do not buy InternetOfThings stuff. As long as it's only accessible locally you should be good. And then you can expose to yourself on the Internet via VPN or something with https://www.home-assistant.io/