Web browsers are where we are most vulnerable for Privacy and Security violations on our Mac. Yes, there are weaknesses in the macOS and possibly some other Apps, but we use web browsers more than any other App. We go more places outside our computing eco-system, thus we are exposed to more potential security problems. This article covers just about everything known to man about security and privacy settings in the Safari web browser. I highly recommend you read it. You may be doing some of these things, but I doubt you are doing all of them.