I can easily imagine that there's an identity for me at Google which is linked to all the IP I had ever used (meaning country and ISP at the least), and linked to every google account I ever used and browser ever used (meaning what devices I've been using) and then every page I've visited which has Google ads or analytics (meaning what site I visit) and every keyword I used to search the web (easy to guess what kind of life I'm having) and then every location I've ever searched on their map (meaning they know where I go and perhaps roughly where I live).

They know more about your online history than yourself they can write a diary for you but if you feel comfortable with that, then you don't need to do anything.

Changing IP, clearing cookie and changing browser may divide your ID but as soon as you log in with your Google account or they realize you may be having identical online activities, you can easily get linked again.

And as soon as you buy something on your Google account, be it physical item or an in app purchase, they know your real identity along with all of the above and then with more profiling, you will be linked with other people by family name, location you often visit and recognized by any other profiling I can't think of now.