The only aspect of this story which surprises me is that 25% of iOS users opted in to tracking.
I really nearly fainted when I saw my location history on google and now that I have a firewalled Huawei with Google forbidden on it, I finally feel a bit location-safe :D And it's not that I care that americans know where I am, it's that people can just get my phone/account, people close to me, and track me, eww.
I really am impressed you found relevant stuff on instagram, but I found that desiring less things is usually just as rewarding as getting an add for the right flavor of yoghurt.
It's mostly been small alternative-type stores, typically for clothes which I'd have never even found out about otherwise but match my aesthetic presumably because they just advertise to a niche audience like me based on the data.