Like literally, my screen only had pictures of multimeters.
For good measure I repeated the search in my main Youtube account. Same thing.
It's likely some coincidence of my previous viewing history, though how woodworking, small engine repair and distributed systems pointed to grossout videos I have no idea. I've heard of at least a dozen other people that this happens to so far across a wide range of viewing habits.
Lots of sponsored ads, but they are all multimeter-related.
So if YouTube is tracking me across incognito mode, then they aren't doing a very good job there.