Can someone answer whether this includes deleted search histories? I specifically go through and delete my search history. I’ve never searched anything illegal to my knowledge. But according to this you never know what will be illegal in the future.
There is no free lunch in this problem. You have to consistently protect yourself and your household network to avoid tracking. Also you will probably never be able to stop it fully. Understanding the ecosystem and how tracking works will help a lot and understanding your individual tolerance for tracking is crucial. I personally think it's hygienic to test out anti-tracking measures and I go for sprints with all of them running but also I use the internet like a nearly normal user a lot of the time.
If you want to take steps to learn more a good place to start is using an old computer or raspberry pi and try out some network level filtering like PiHole, having separate networks for IoT devices/mobile devices/home users/guests and doing routing to a VPN you set up yourself via a cloud host selectively for traffic, times of day, and device.