Yeah my guess is that OP is on Windows, judging by the way they mention advertising. This is the way I used to think and now that I am solely on macOS and Linux for my personal computing tasks, I don’t feel like that any more, though I am not foolish enough to believe that even on those systems you can’t be spied on at a hardware or OS level. Even if you’re on a theoretically 100% secure OS, any third-party software such as, oh, a browser, could be phoning home or have analytics hooks that track all kinds of things. If you’re super paranoid, I suppose you could always install Kali Linux on a VM and run TOR on that for covert communications. Or use smoke signals and manual OTPs.