I only ever browse Youtube in an incognito window, and to watch a video I copy its URL, yt-dlp it, and play it with VLC. I do similar things with other sites likely to track me: I tend to open them in incognito windows. (Which, of course, doesn't make it impossible to track me, just harder). So they have some data on me — it's impossible to hide your every move from the Google panopticon — but a lot less than with most people.

So yes, just as with your example, it was pretty obvious when the targeting algorithm acquired new data.