Anything more than necessary. Why do you want them to know? I wouldn’t let a stranger follow me around, so why should I allow a tracking cookie on my browser? It’s scary and offensive.

Suppose a bad actor gets access to this information. Suppose this bad actor has the “political view” that people with your specific profile shouldn’t be allowed to vote. Suppose they have the network to get a small army of really big guys to stand in front of your house on election day. That’s a very superficial example on why you shouldn’t want companies to have any of your data unless it’s necessary.

my personal problem isn’t the fact that they know a lot about me, but the fact that they can sell that information to advertisers and make millions of dollars of something I didn’t give them willingly (sure, knowingly but not willingly)

Anything I wouldn’t tell a random stranger. Like who are my friends, their phone numbers, where I live, my full name, my location at all times, etc.

I don’t want them to know anything that isn’t completely necessary, and even that should be wiped as soon as it’s no longer relevant. Why should I be okay with corps recording all of my online behavior and preferences just so they can sell that info for a bit of extra profit?