I'm afraid you are making a mistake in assuming that Incognito mode == no tracking. The only thing that Incognito mode does is not save any local history or cookies. This is mainly of benefit for people who share a computer and don't want the other users to see their history.
Tracking has long moved way beyond cookies and Google is absolutely tracking what you do in incognito mode and doing their best (which is highly effective) to associate the tracking data with you.
You can delete your watch history after every session or have something automated do it for you. That will work fine if you only want to watch the content you subscribed to.
If you want better recommendations though you may have to tolerate some things that you may consider "spying".
You'd also have to trust that YT doesn't track you in the incognito window, given that it's still pretty easy to identify an user and you're also most likely using Google's own browser to hide.
If you really don't want to be tracked by Google, you should probably consider not using their services.
Also cute these people think using incognito does anything to stop Google from tying the traffic back to them. They already finger print you off hundreds of parameters. Hell most people are literally using their web browser.