I use YouTube on windows 10. Even though I have a Google account, I do not log into Google. I always have a "Sign In" button on YouTube, never my account name.
On Internet Explorer’s "general tab" I have checked "delete browsing history on exit" and on the privacy tab "never allow websites to request your physical location."
Even though I don't log in, I used Google MyActivity website
https://myactivity.google.com
First I choose "delete history" webpage, and after much pleading from Google, deleted all my history.
Then I went to the innocuously name "Activity controls" and "paused" Google's tracking. I have done this before, but at some point Google's decided to "unpause" it, without telling me. >:(
Yet even after I quit, and restart my PC, I get recommended videos that obviously are based on my previous searches.
For example, I was watching some 1940's PeriscopeFilm videos yesterday. Today the home page recommends a bunch of WWII videos.
Obviously Google / YouTube is tracking my previous searches, despite going to great lengths to stop it.