Memes

Whether they do or not, Google doesn’t know that that person is the same person as the one who is using YouTube.

I exaggerated for effect, in the way that 99% sure might as well be a fact in this case:

I have never given them to YouTube, and they have no financial incentive to acquire them AFAIK - holding that kind of PI is a liability so if anything they wouldn't want it without having a need for it. YouTube can't even know what countries I live in, my digital identity from the POV of their servers is too fluid and non-unique for my viewing habits to meaningfully correlate; I blend in with many other people also trying to stay hidden from them.

As for other Alphabet companies, like those engaged in surveillance capitalism who want to scoop up all of the datas, it's theoretically possible they've illegally acquired them from third parties and found a use for it, but there's just no feasible way they could associate that with most of my online activities, say, this account I'm using. The only people who have a chance at that are certain state intelligence agencies who are eavesdropping the wires, and they have much bigger problems they're paid to worry about. Hell, unless things have gotten better for them since Snowden, even they might struggle - most of their super cool hacker shit is only really useful if someone's worth active targeting.