It’s pretty obvious ads are targeted everywhere today, you search for Adidas running shoes and you expect to see running shoes ads in YouTube, Instagram, Amazon and pretty much every single platform with an ad revenue model. It’s not a subtle, subliminal thing buried into text nudging you into buying shoes, but very evident, pretty much your exact search query transformed into highly visual content. I would be shocked if I know someone under 60 that does not know this.

When I watch YouTube on an Apple TV the ads seem slightly relevant - when I watch on a mobile device they are completely awful, literally no idea why I'm being shown most of them.

You probably disabled some privacy settings on your mobile (or you are not logged in with your user).

Definitely logged in using the same account.

If anything people overestimate the amount of tracking since the average person still thinks their phones are giving them ads based on what they say

Yeah, the incident rate of this occurring is pretty high for randomness only.

It's easier to expect that your phone is always listening (because it is) and sending that data to apps for advertising than to force app providers to open source their code and prove they aren't collecting data on what the phone mic picks up.

But maybe you have more insight on a single provider's application that has been thus accused than other people in the thread.